tony moore said:
i changed the intake gasket on my 97 Z71 1500 pickup with a 350 vortec. it has been a few months and ever since it has a code set, check engine light is on. it comes up o2 sensor so i changed it and light is still on. now it wont run when its cold it will cut off(stall) when idling and skip and buck at part throttle till it warms up and then it runs fine!i marked the dist. and put it back as it came out but someone said i need to set it by voltage. :dunno: help please it runs so bad now i havent drove it in a few weeks!!
Was it a P0171 or P0174? If so, thats NOT an O2 sensor code, but a system lean code. Most likely due to the cam retard not being set and fuel timing is off. You probably marked the dist when you pulled it, but being off 4+ degrees can throw fuel timing off enough to code lean, but not out of sync.
Symptoms are as you describe. It may even feel like EGR is coming on too early. But thats the dist being out. The distributor in these trucks have ZERO to do with ignition timing. Its all fuel timing. Ignition is based off crank sensor
You need to hook up with somoene with a scanner that will show the cmp retard pid, and get it down to zero. After each adjustment you must rev the engine past 1000rpm for the pid to update.