02 Buick 3.8 problem

I've got a 2002 Buick Regal that has an engine problem. It's the 3.8L
engine and it runs good up to about 4000 RPM then starts losing power
and missing badly. There are no codes when checked with the scan tool.
Speed makes no difference, in fact it will do it in neutral too. Any
ideas would be appreciated!

Dave

It's normal on your car for the PCM to limit RPM to 4000 while in park or
neutral, but not in other gear ranges. I would suspect a faulty plug, wire,
or coil, but that should lead to a SERVICE ENGINE SOON light with a code
indicating one or more misfires. Another possibility is that the
transmission range switch or associated wiring is faulty, causing the PCM to
think the vehicle is always in park or neutral, thus limiting RPM to 4000.
Does your cruise control work? Does the gear range indicator on your dash
always show the proper selected gear? Any other symptoms? What is the
mileage on the vehicle?

Roger

If it's doing this while in drive, then i'd suspect a faulty plug, wire, or
coil. However, you'd probably have an SES light with codes indicating
misfires. Another possibi
"Dave B" > wrote in message
...
> I've got a 2002 Buick Regal that has an engine problem. It's the 3.8L
> engine and it runs good up to about 4000 RPM then starts losing power and
> missing badly. There are no codes when checked with the scan tool. Speed
> makes no difference, in fact it will do it in neutral too. Any ideas would
> be appreciated!
>
> Dave

Ignore the partial info below my signature on that last post. I goofed
up.

Thanks Roger, it's been getting worse and now does it almost anytime I
try to accelerate. The symptoms seemed to point to a bad catalytic
converter so I checked the backpressure at the exhaust manifold and
after the converter and had about 10psi before (at 4k rpm), and nothing
readable after. The book says it should be 1.25psi, so maybe I found it.
My original post said it was missing and that may have been inaccurate.
It was "dropping out/falling on it's face", but those symptoms were
mostly in park, and I understand now, that is normal. On the road it was
more a loss of power and no acceleration.
Dave

Dave B wrote:
> Thanks Roger, it's been getting worse and now does it almost anytime I
> try to accelerate. The symptoms seemed to point to a bad catalytic
> converter so I checked the backpressure at the exhaust manifold and
> after the converter and had about 10psi before (at 4k rpm), and nothing
> readable after. The book says it should be 1.25psi, so maybe I found it.
> My original post said it was missing and that may have been inaccurate.
> It was "dropping out/falling on it's face", but those symptoms were
> mostly in park, and I understand now, that is normal. On the road it was
> more a loss of power and no acceleration.
> Dave
Ok, the problem was the catalytic converter and the dealer replaced it
in warranty. Thanks for your help!
Dave