Hello, any info would be appreciated on a problem I am having with a 1991 cavalier rs, 2.2 I-4 automatic.

I just built a 0.040 over 2.2 flat tappet motor for this car and replaced all the normal wear and tear parts with new ones (long list). I also installed a new crank timing sensor as well as a module. I reused the coil packs as they tested within proper operating range.
My problem is this; The car runs great when cold and runs fine down the highway for unlimited miles. However when it is forced to idle in traffic for a semi-lengthy amount of time it will stall while in gear if it is brought to a full stop. It will always crank back up immediately and idle fine in neutral, however placing it in gear will cause it to die again without an excessive amount of rpm, to get moving again.
My first guess is that the ignition coils are getting heat soaked and producing a weak spark at full operating temperature, as I can feel the power is down and the acceleration is weak when this happens.
I am open to anyone with experience or an idea on how to diagnose this problem, thank you.

 

my 93 did that at one point before...me and my bf changed the coil packs and my car worked after that...

 

having same prob. w. beretta 2.2 (same motor). Friend said it was idle air sensor after testing w. scanner, but replacing it didn't work. Please post again if you get yours fixed so I'll know what to try.

 

its like driving a manual and stalling it,correct? my gf's 94 did the same thing so we topped up the tranny fluid and its been going good. maybe we just fluked out

 

I just had the 2.2 in my 91 rebuilt and have the same problemintermittently, sometimes with the check engine lighton. The rebuilding shop hooked up the diagnostic computer and the error code showed that the EGR valve isn't working properly.Adding fuel injection cleaner to a couple of tankfuls may help.