Greetings,

My first post...and problem.

1997 Blazer s10 225k miles

Symptom:
Runs perfect when cold....idles, revs up, accelerates fine...NO codes
seen while frequently monitoring. After about 10-15 minutes, stumbling
and tach swings of several hundred RPM when it reaches about 2800 RPM
or more. Then, I stop the car, check for codes and get PO 339 and sometimes
PO 339 and PO 141. If I then erase the codes and just rev it up with no load,
it misfires a lot at about 3000 RPM and higher....and I get the two codes again.

I know the codes refer to the cam and crank sensors...and I have new ones
ready to install, but am stumped as to why it runs great when cold..with
no codes picked up. Any suggestions appreciated....thanks.

-Dave

 

I think I am on my way to solving my problem.

Pulled the sensor out, and saw lots of marking of the tip. I went to my local
hardware store and bought two .02 fiber washers.
I painted the tip of the sensor with blue Dykem and will
add one washer and try it out.....

 

Solved all problems by putting $.02 shim fibre washer in crank sensor.....!!!!!!!!!!!!!!

 

You need to do the crankshaft position sensor relearn. If/when the sensor or timing cover are moved, removed, replaced, or disturbed in any way, the relearn must be done. If you don't do it, the PCM will continue to use relearn data from the original position of the CKP sensor, which is now incorrect data. The engine will still start and run, but cylinder misfire detection, cylinder identification, along with ignition and injector timing, will not be accurate.