1998 Jeep Cherokee power loss, missing, no codes...TPS??

Hey y'all;

I've got one of those "mystery problems," could use some help. I drive
98 Cherokee Sport, 4.0L inline 6, with manual transmission, around 110K
miles. The problem I have is this: at about 2000 RPM, the engine
loses power and sometimes misses. During the latter incidents, it acts
as though its not getting enough fuel, something like the beginnings of
a fuel pump dying but not as severe. The problem is more pronounced if
under load (AC on, carrying heavy stuff, going uphill..) or in higher
gear ranges, and seems to be worse when the outside air temperature
changes rapidly. Gas mileage has dropped by about 5-6 mpg since the
problem started.

So far, several visits to the dealership have been fruitless. There are
no codes being generated, so there's not much to go on. The oxygen
sensor was replaced a few months before the current issue started due
to a different problem, and the throttle body & connections thoroughly
cleaned then, too. The dealership tried to tell me I had "weak valve
springs" and needed a complete engine overhaul ($800+) to replace them,
which did not sound right to me at all. I've had a lot of trouble
finding a good garage nearby, so I'm ready to start tinkering myself in
what little spare time I have. :-(

I've seen a lot of stuff on here about bad TPS sensors and/or bad
connections, could this be the cause of my problem, too? I don't have
a big toolkit nor am I terribly knowledgeable about fuel systems or
testing voltages and such, so I'm not sure how best for me to start
working with this. I bought a Haynes Manual a long time ago, but it
doesn't have much info in it about sensors & such for the 1998 model (&
newer).

Also, just recently, it has started with a new problem: when I turn on
the left turn signal, both lights blink as though I'd turned on the
hazards. Doesn't happen with the right blinker, doesn't happen if the
ignition is off and the car parked, only when running & in motion.
Almost simultaneously, the rear passenger electric door lock mechanism
began malfunctioning, and refusing to lock or unlock while making a
nasty grinding noise. I have no idea if these problems could be related
in any way (grounds gone bad? shorts? lightning? ) but I just wanted to
mention them in case they are clues.

Thanks for whatever help you can offer.

I'm going to believe your Stealership, and confirm weak valve
springs act the way describe. And they have the equipment that tests for
that, and so does your Cherokee's Onboard Diagnostics:
http://www.wjjeeps.com/faultcodes.htm There are mechanics that will
replace them without pulling the head to cut the labor in half.
God Bless America, Bill O|||||||O
http://www.billhughes.com/

katuah wrote:
>
> Hey y'all;
>
> I've got one of those "mystery problems," could use some help. I drive
> 98 Cherokee Sport, 4.0L inline 6, with manual transmission, around 110K
> miles. The problem I have is this: at about 2000 RPM, the engine
> loses power and sometimes misses. During the latter incidents, it acts
> as though its not getting enough fuel, something like the beginnings of
> a fuel pump dying but not as severe. The problem is more pronounced if
> under load (AC on, carrying heavy stuff, going uphill..) or in higher
> gear ranges, and seems to be worse when the outside air temperature
> changes rapidly. Gas mileage has dropped by about 5-6 mpg since the
> problem started.
>
> So far, several visits to the dealership have been fruitless. There are
> no codes being generated, so there's not much to go on. The oxygen
> sensor was replaced a few months before the current issue started due
> to a different problem, and the throttle body & connections thoroughly
> cleaned then, too. The dealership tried to tell me I had "weak valve
> springs" and needed a complete engine overhaul ($800+) to replace them,
> which did not sound right to me at all. I've had a lot of trouble
> finding a good garage nearby, so I'm ready to start tinkering myself in
> what little spare time I have. :-(
>
> I've seen a lot of stuff on here about bad TPS sensors and/or bad
> connections, could this be the cause of my problem, too? I don't have
> a big toolkit nor am I terribly knowledgeable about fuel systems or
> testing voltages and such, so I'm not sure how best for me to start
> working with this. I bought a Haynes Manual a long time ago, but it
> doesn't have much info in it about sensors & such for the 1998 model (&
> newer).
>
> Also, just recently, it has started with a new problem: when I turn on
> the left turn signal, both lights blink as though I'd turned on the
> hazards. Doesn't happen with the right blinker, doesn't happen if the
> ignition is off and the car parked, only when running & in motion.
> Almost simultaneously, the rear passenger electric door lock mechanism
> began malfunctioning, and refusing to lock or unlock while making a
> nasty grinding noise. I have no idea if these problems could be related
> in any way (grounds gone bad? shorts? lightning? ) but I just wanted to
> mention them in case they are clues.
>
> Thanks for whatever help you can offer.

Someone else on this group had one of the engines with the bad valve
springs. Jerry B I think....

There are some engines out there with the bad springs, that's for sure.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

katuah wrote:
>
> Hey y'all;
>
> I've got one of those "mystery problems," could use some help. I drive
> 98 Cherokee Sport, 4.0L inline 6, with manual transmission, around 110K
> miles. The problem I have is this: at about 2000 RPM, the engine
> loses power and sometimes misses. During the latter incidents, it acts
> as though its not getting enough fuel, something like the beginnings of
> a fuel pump dying but not as severe. The problem is more pronounced if
> under load (AC on, carrying heavy stuff, going uphill..) or in higher
> gear ranges, and seems to be worse when the outside air temperature
> changes rapidly. Gas mileage has dropped by about 5-6 mpg since the
> problem started.
>
> So far, several visits to the dealership have been fruitless. There are
> no codes being generated, so there's not much to go on. The oxygen
> sensor was replaced a few months before the current issue started due
> to a different problem, and the throttle body & connections thoroughly
> cleaned then, too. The dealership tried to tell me I had "weak valve
> springs" and needed a complete engine overhaul ($800+) to replace them,
> which did not sound right to me at all. I've had a lot of trouble
> finding a good garage nearby, so I'm ready to start tinkering myself in
> what little spare time I have. :-(
>
> I've seen a lot of stuff on here about bad TPS sensors and/or bad
> connections, could this be the cause of my problem, too? I don't have
> a big toolkit nor am I terribly knowledgeable about fuel systems or
> testing voltages and such, so I'm not sure how best for me to start
> working with this. I bought a Haynes Manual a long time ago, but it
> doesn't have much info in it about sensors & such for the 1998 model (&
> newer).
>
> Also, just recently, it has started with a new problem: when I turn on
> the left turn signal, both lights blink as though I'd turned on the
> hazards. Doesn't happen with the right blinker, doesn't happen if the
> ignition is off and the car parked, only when running & in motion.
> Almost simultaneously, the rear passenger electric door lock mechanism
> began malfunctioning, and refusing to lock or unlock while making a
> nasty grinding noise. I have no idea if these problems could be related
> in any way (grounds gone bad? shorts? lightning? ) but I just wanted to
> mention them in case they are clues.
>
> Thanks for whatever help you can offer.

True.
God Bless America, Bill O|||||||O
http://www.billhughes.com/

Mike Romain wrote:
>
> Someone else on this group had one of the engines with the bad valve
> springs. Jerry B I think....
>
> There are some engines out there with the bad springs, that's for sure.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> (More Off Road album links at bottom of the view page)

If all you need is new springs you can do that yourself.

They make adapters that thread into the spark plug holes that use air
pressure to hold the valves closed and you can compress and remove the old
ones with the head still on the engine.

If you think you may need or benefit from a valve job you can pull the head
in your driveway and have your corner machine shop work on the head and you
reinstall it.

The labor involved is pretty straightforward and you can save yourself a ton
of labor charges.


"Mike Romain" > wrote in message
...
> Someone else on this group had one of the engines with the bad valve
> springs. Jerry B I think....
>
> There are some engines out there with the bad springs, that's for sure.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> (More Off Road album links at bottom of the view page)
>
> katuah wrote:
>>
>> Hey y'all;
>>
>> I've got one of those "mystery problems," could use some help. I drive
>> 98 Cherokee Sport, 4.0L inline 6, with manual transmission, around 110K
>> miles. The problem I have is this: at about 2000 RPM, the engine
>> loses power and sometimes misses. During the latter incidents, it acts
>> as though its not getting enough fuel, something like the beginnings of
>> a fuel pump dying but not as severe. The problem is more pronounced if
>> under load (AC on, carrying heavy stuff, going uphill..) or in higher
>> gear ranges, and seems to be worse when the outside air temperature
>> changes rapidly. Gas mileage has dropped by about 5-6 mpg since the
>> problem started.
>>
>> So far, several visits to the dealership have been fruitless. There are
>> no codes being generated, so there's not much to go on. The oxygen
>> sensor was replaced a few months before the current issue started due
>> to a different problem, and the throttle body & connections thoroughly
>> cleaned then, too. The dealership tried to tell me I had "weak valve
>> springs" and needed a complete engine overhaul ($800+) to replace them,
>> which did not sound right to me at all. I've had a lot of trouble
>> finding a good garage nearby, so I'm ready to start tinkering myself in
>> what little spare time I have. :-(
>>
>> I've seen a lot of stuff on here about bad TPS sensors and/or bad
>> connections, could this be the cause of my problem, too? I don't have
>> a big toolkit nor am I terribly knowledgeable about fuel systems or
>> testing voltages and such, so I'm not sure how best for me to start
>> working with this. I bought a Haynes Manual a long time ago, but it
>> doesn't have much info in it about sensors & such for the 1998 model (&
>> newer).
>>
>> Also, just recently, it has started with a new problem: when I turn on
>> the left turn signal, both lights blink as though I'd turned on the
>> hazards. Doesn't happen with the right blinker, doesn't happen if the
>> ignition is off and the car parked, only when running & in motion.
>> Almost simultaneously, the rear passenger electric door lock mechanism
>> began malfunctioning, and refusing to lock or unlock while making a
>> nasty grinding noise. I have no idea if these problems could be related
>> in any way (grounds gone bad? shorts? lightning? ) but I just wanted to
>> mention them in case they are clues.
>>
>> Thanks for whatever help you can offer.

My 97 i6 has acted similarly. I have had others describe my problem as weak
springs also. I have also left mine with the dealership for days, only to
get back the same jeep problem (but $150 poorer..). The last time I tried
that was a couple years ago. They didn't believe in the weak spring thing,
they thought it would act the same way all the time if that were the case,
not just high rpm and under load. I don't believe them. Still seems like
weak springs.
I know the best way to get by this is to replace the spings. What I have
done is to use Seafoam. I pour about half a can slowly in the throttle body
at idle (or a little above idle), add the rest to the gas, and I am 'cured'
for about a year. ( Follow instructions on the can.) I tried the new plugs
and wires suggested by the dealership, and this is the only thing that has
worked for me. Of course, if you have the cash or time, replace the
springs. Especially since with this cheap fix , you're never really sure
about that trip to the mountains......

cal


"billy ray" > wrote in message
...
> If all you need is new springs you can do that yourself.
>
> They make adapters that thread into the spark plug holes that use air
> pressure to hold the valves closed and you can compress and remove the old
> ones with the head still on the engine.
>
> If you think you may need or benefit from a valve job you can pull the
> head in your driveway and have your corner machine shop work on the head
> and you reinstall it.
>
> The labor involved is pretty straightforward and you can save yourself a
> ton of labor charges.
>
>
> "Mike Romain" > wrote in message
> ...
>> Someone else on this group had one of the engines with the bad valve
>> springs. Jerry B I think....
>>
>> There are some engines out there with the bad springs, that's for sure.
>>
>> Mike
>> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>> 88 Cherokee 235 BFG AT's
>> Canadian Off Road Trips Photos: Non members can still view!
>> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
>> (More Off Road album links at bottom of the view page)
>>
>> katuah wrote:
>>>
>>> Hey y'all;
>>>
>>> I've got one of those "mystery problems," could use some help. I drive
>>> 98 Cherokee Sport, 4.0L inline 6, with manual transmission, around 110K
>>> miles. The problem I have is this: at about 2000 RPM, the engine
>>> loses power and sometimes misses. During the latter incidents, it acts
>>> as though its not getting enough fuel, something like the beginnings of
>>> a fuel pump dying but not as severe. The problem is more pronounced if
>>> under load (AC on, carrying heavy stuff, going uphill..) or in higher
>>> gear ranges, and seems to be worse when the outside air temperature
>>> changes rapidly. Gas mileage has dropped by about 5-6 mpg since the
>>> problem started.
>>>
>>> So far, several visits to the dealership have been fruitless. There are
>>> no codes being generated, so there's not much to go on. The oxygen
>>> sensor was replaced a few months before the current issue started due
>>> to a different problem, and the throttle body & connections thoroughly
>>> cleaned then, too. The dealership tried to tell me I had "weak valve
>>> springs" and needed a complete engine overhaul ($800+) to replace them,
>>> which did not sound right to me at all. I've had a lot of trouble
>>> finding a good garage nearby, so I'm ready to start tinkering myself in
>>> what little spare time I have. :-(
>>>
>>> I've seen a lot of stuff on here about bad TPS sensors and/or bad
>>> connections, could this be the cause of my problem, too? I don't have
>>> a big toolkit nor am I terribly knowledgeable about fuel systems or
>>> testing voltages and such, so I'm not sure how best for me to start
>>> working with this. I bought a Haynes Manual a long time ago, but it
>>> doesn't have much info in it about sensors & such for the 1998 model (&
>>> newer).
>>>
>>> Also, just recently, it has started with a new problem: when I turn on
>>> the left turn signal, both lights blink as though I'd turned on the
>>> hazards. Doesn't happen with the right blinker, doesn't happen if the
>>> ignition is off and the car parked, only when running & in motion.
>>> Almost simultaneously, the rear passenger electric door lock mechanism
>>> began malfunctioning, and refusing to lock or unlock while making a
>>> nasty grinding noise. I have no idea if these problems could be related
>>> in any way (grounds gone bad? shorts? lightning? ) but I just wanted to
>>> mention them in case they are clues.
>>>
>>> Thanks for whatever help you can offer.
>
>

Be aware you may have to clean or replace your spark plugs after the SeaFoam
Treatment.


"Cal" > wrote in message
...
> My 97 i6 has acted similarly. I have had others describe my problem as
> weak springs also. I have also left mine with the dealership for days,
> only to get back the same jeep problem (but $150 poorer..). The last time
> I tried that was a couple years ago. They didn't believe in the weak
> spring thing, they thought it would act the same way all the time if that
> were the case, not just high rpm and under load. I don't believe them.
> Still seems like weak springs.
> I know the best way to get by this is to replace the spings. What I have
> done is to use Seafoam. I pour about half a can slowly in the throttle
> body at idle (or a little above idle), add the rest to the gas, and I am
> 'cured' for about a year. ( Follow instructions on the can.) I tried the
> new plugs and wires suggested by the dealership, and this is the only
> thing that has worked for me. Of course, if you have the cash or time,
> replace the springs. Especially since with this cheap fix , you're never
> really sure about that trip to the mountains......
>
> cal
>
>
> "billy ray" > wrote in message
> ...
>> If all you need is new springs you can do that yourself.
>>
>> They make adapters that thread into the spark plug holes that use air
>> pressure to hold the valves closed and you can compress and remove the
>> old ones with the head still on the engine.
>>
>> If you think you may need or benefit from a valve job you can pull the
>> head in your driveway and have your corner machine shop work on the head
>> and you reinstall it.
>>
>> The labor involved is pretty straightforward and you can save yourself a
>> ton of labor charges.
>>
>>
>> "Mike Romain" > wrote in message
>> ...
>>> Someone else on this group had one of the engines with the bad valve
>>> springs. Jerry B I think....
>>>
>>> There are some engines out there with the bad springs, that's for sure.
>>>
>>> Mike
>>> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>>> 88 Cherokee 235 BFG AT's
>>> Canadian Off Road Trips Photos: Non members can still view!
>>> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
>>> (More Off Road album links at bottom of the view page)
>>>
>>> katuah wrote:
>>>>
>>>> Hey y'all;
>>>>
>>>> I've got one of those "mystery problems," could use some help. I drive
>>>> 98 Cherokee Sport, 4.0L inline 6, with manual transmission, around 110K
>>>> miles. The problem I have is this: at about 2000 RPM, the engine
>>>> loses power and sometimes misses. During the latter incidents, it acts
>>>> as though its not getting enough fuel, something like the beginnings of
>>>> a fuel pump dying but not as severe. The problem is more pronounced if
>>>> under load (AC on, carrying heavy stuff, going uphill..) or in higher
>>>> gear ranges, and seems to be worse when the outside air temperature
>>>> changes rapidly. Gas mileage has dropped by about 5-6 mpg since the
>>>> problem started.
>>>>
>>>> So far, several visits to the dealership have been fruitless. There are
>>>> no codes being generated, so there's not much to go on. The oxygen
>>>> sensor was replaced a few months before the current issue started due
>>>> to a different problem, and the throttle body & connections thoroughly
>>>> cleaned then, too. The dealership tried to tell me I had "weak valve
>>>> springs" and needed a complete engine overhaul ($800+) to replace them,
>>>> which did not sound right to me at all. I've had a lot of trouble
>>>> finding a good garage nearby, so I'm ready to start tinkering myself in
>>>> what little spare time I have. :-(
>>>>
>>>> I've seen a lot of stuff on here about bad TPS sensors and/or bad
>>>> connections, could this be the cause of my problem, too? I don't have
>>>> a big toolkit nor am I terribly knowledgeable about fuel systems or
>>>> testing voltages and such, so I'm not sure how best for me to start
>>>> working with this. I bought a Haynes Manual a long time ago, but it
>>>> doesn't have much info in it about sensors & such for the 1998 model (&
>>>> newer).
>>>>
>>>> Also, just recently, it has started with a new problem: when I turn on
>>>> the left turn signal, both lights blink as though I'd turned on the
>>>> hazards. Doesn't happen with the right blinker, doesn't happen if the
>>>> ignition is off and the car parked, only when running & in motion.
>>>> Almost simultaneously, the rear passenger electric door lock mechanism
>>>> began malfunctioning, and refusing to lock or unlock while making a
>>>> nasty grinding noise. I have no idea if these problems could be related
>>>> in any way (grounds gone bad? shorts? lightning? ) but I just wanted to
>>>> mention them in case they are clues.
>>>>
>>>> Thanks for whatever help you can offer.
>>
>>
>
>

I had the same symptoms with my 90 XJ, it was the O2 sensor. I would
double check the connection, all connections for that matter as they
have always been a problem on XJ's.

The O2 sensor for the Renix system on the 88-91 XJ is under recall!

If you haven't had the recall done it is a freebie still.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

wrote:
>
> I had the same symptoms with my 90 XJ, it was the O2 sensor. I would
> double check the connection, all connections for that matter as they
> have always been a problem on XJ's.

Hey Bill;

I have to ask, what is the defining thing to make you believe it is the
springs? I ask because I had thought that weak springs would cause
"clacking" if they weren't doing their job, sort of like a
redlined/overrotated engine, only starting at lower RPM's, but this
problem appears primarily at only around 2000 RPM (which seems really
low), and actually seems to lessen at higer RPM's (22-2500).

Is there a way to know besides the coded diagnostic, because the
computer tester at the dealership showed nothing of the sort -
actually, showed nothing at all, per the mechanics there.