gm junk 06 cobalt 2.2 misfirre

after replacing ckp sensor (crankshaft position sensor) car no longer
dies but still missfires only on cold starts. never at the dealers
though. codes p0300 p0336 p0106 before i replaced sensor

On Aug 7, 7:23*am, nate > wrote:
> after replacing ckp sensor (crankshaft position sensor) car no longer
> dies but still missfires only on cold starts. never at the dealers
> though. codes p0300 p0336 p0106 before i replaced sensor

So the P0300 is a 'random misfire', which based on your limited
information, sounds plausible. P0336 does not mean 'bad crankshaft
position sensor' however, and if you replaced the sensor on this code
alone without diagnosing the system you may have thrown parts into the
mix unnecessarily. P0336 is a -bad signal- from the CKP, but not a
LACK of signal.....which could be due to a bad sensor, or a damaged
pickup wheel(incorrect gap, physical damage to the prongs), or damaged/
frayed wiring in the loom somewhere.

P0106 is an interesting code because it indicates a problem with the
MAP sensor. A problem in this area could throw the mixture off enough
to create the right conditions for both a misfire -and- a bad signal
from the CKP, after all, if the engine isn't firing correctly and the
ECM expects regular pulses from the CKP, it may not get them if the
mixture is going far too rich or far too lean.

If it was my car, I'd look into the P0106 first and troubleshoot that
initially. The fact that you said it only misfires on a cold start is
a good clue. I'd check the connections to the MAP, maybe take it out
and clean it or swap it for another. You didn't mention how many miles
are on the car or any other information(Has it been overheated?
Crashed? Has it gotten regular maintenance?). All of those could play
into sensor failure. Hell, it could be dirty fuel injectors...or a bad
plug. Hence the question about maintenance and mileage.

One thing you need to keep in mind is that an OBD-II code indicates a
problem in a -CIRCUIT-, not necessarily a sensor. I'd hedge a bet that
you'll find a problem somewhere in the air/fuel metering system that
when repaired will cure the other two codes.

I've driven cobalts several times and found them to be nice cars that
have a bit of pep. If you're calling it junk, maybe you should just
trade it?

Good luck with it.

Chris