Strange "Warm Weather" Problem

[Joe71]

Anyone ever seen anything like this?

I drive a 1999 Chevy Cavalier and it appears that it's developing a problem that only shows itself when it's warm (over 70 degrees) outside. I work second shift, commute 15 minutes each way. Today it was 80 degrees out and it started immediately - the car starts bucking and shuddering, in low gear it seems to roughly shift into second and my ETS OFF light comes on. The last time I saw that it had to do with the tranny but I don't think it's the tranny this time. Anyway, lots of resistance, the tachometer keeps spiking by say....100 RPM and the engine revs while the car continues to shudder. Tonight, I came home and I swear, I TRIED to recreate any of this and it wouldn't happen. Completely smooth ride home, not even the first sign of a shudder. It was also 25 degrees cooler outside now. Anyone have any guess as
to what's happening?

[-Jayson-]

yo know i had that same thing with my 95 cav 2.2L. But it didnt notice it in warm weather as much as did in wet weather. BUt when you punch it, you can hear the RPMS shoot through the roof, but you accelerate like your barely touching the gas, then once it gets into 2nd boom it shifts hard as hell. I noticed that once the car gets a good warm up that it stops. I took it to my mechanic to find out what was wrong, he couldnt find anything. Its not a trans problem cause the shudder is still there when you put the car in neutral. Im thinking its a bad start coil, cause i had one go outbefore when i had a leak in the headgasket, coolant was leaking onto it. Then after i got another leak and had it fixed i dont think i ever replaced the starter coil.

[gmcav/ventureowner]

Try getting to the throttle body intake.
On my '98 Z24 I had to remove two bolts and loosen two screws to open up the end of the throttle body (this was opposite where the cable attaches)
Anyway, once open you can move the throttle butterfly and look inside for any residue. Carburetor cleaner is the best for removing this residue.
What may be happening is this butterfly is sticking and the carb cleaner will remove this problem.
Hope this helps.