Having problems with my 92 pontiac bonnie. For starters, 4yrs ago, I had a new bf goodritch engine block installed. A new transmission and a supercharger all done at dealer . I always put 93 octane gas but about one month ago I put 89 octane. The first week, it was fine. Then the problems began. The car had a rough start in the morning, a little bit of white smoke appeared and I had to keep my foot on the gas til she warmed up. She was fine for the day. The next morning, I experienced the same problems as previously mentioned. I began off by changing the crank sensor, then things seemed ok for a few days, except for the rough start. I also changed the coil pack, the module under the coil pack, wires, spark plugs, stater, egr valve, oxygen sensor and I'm still having rough start problems. Somebody told me about a cold start relay/sensor or cold start injector. I am not sure exactly what or where in the car this is. Does this sound to you like this is my problem?

I deleted your quoted reply to yourself. There is no need to "bump" your topic ten minutes after starting it

Welcome to BonnevilleClub, you came to the right place for help We will get you all fixed up and running good in no time


Your post is somewhat difficult to follow, everything is kind of just run togather and is hard to understand. Can you edit it to make it easier to read and understand?



On to your problem...

First thing... if you have any sort of a heavy foot, PREMIUM fuel is absolutely necessary. Running 89 will cause KR, and kill performance, fuel mileage, and will cause damage to your engine. It only costs about $3.50 more per tank to fill up on premium instead of reular. The little money you save by using regular is offset by the worse gas mileage, and worse performance.


As far as the rough cold start goes... Have you ever cleaned the throttle body? Sounds like the Idle Air Control valve is possibly dirty and / or stuck. That will cause a rough cold start / idle.

Also, check ALL of your vacuum lines for any cracks. If you feel the lines, and they leave black on your hands, replace them. Replacing all the vacuum lines will not cost much, and could be considered preventative maintenance.

Moved to 92-99. Please read the section descriptions.

After reading the post for the third time to get it straight in my mind, I also suggest doing a vacuum leak hunt. At idle, spray carb cleaner lightly on every single vac connection you can find. Also inspect the hidden one under your vac accumulator between th WS wiper motor and the maxifuse relay center.

TB and MAF cleaning procedure is in Techinfo.

Have you checked for codes? That'* in Techinfo also.

It does sound like an airflow problem. To veryify, you could find a thin piece of material (a popsick stick works) and stick it behind the throttle plate idle stop before you try your cold start. If the car starts and idles with the throttle propped slightly open, you'll know for sure. Do a thorough throttle body clean. Clean the IAC passages and the IAC motor.

The motor may have problems, too. You can *sort of* check it by removing it and plugging the connector back in. Have somebody cycle the key from "off" to "run" multiple times. The motor should wind in and out. Grab the bullet shaped thing on the end of the little shaft with the little spring over it. Try to turn it back and forth like a **** on a stereo. It should wiggle a bit, but not turn. If it does, the little plastic track that the shaft slides in is stripped out, which is common. You'll need a new IAC motor.

this acv where is it located on the car is it the little black thing with 2 bolts under the throttle body and sorry i dont know what iac moter is,can anybody help me with this