I have a 1995 Bonneville, the non-super charged edition.

The car had a new-used engine put in, a transmission repair, and a new battery approximately 6 months ago. The car has been running flawlessly, save for occasionally not starting the first time you turn the key- Always started right up on a second key turn, however.

It starts right up effortlessly if the engine is nice and cold, but if you drive the car somewhere, turn it off, run into a store, and come out ten minutes later it refuses to start. The engine turns over, and sounds like it would really like to start.. But it never fires.

If I put the car into neutral and nearly floor the gas peddle while turning the key, the car will start. If you try to put it into drive and take off too soon after doing this, the engine will die. You have to sit in the car for at least 5 minutes before taking off if the car is started this way. It also sounds like the car is continuously adjusting it'* idle for a few minutes.

This has been happening for about a week, and it seems like the car needs to sit for at least 3 hours before it will start up without any nonsense.

Once the car is started and on it'* way down the road, it runs great. It does seem like the car randomly chooses to accelerate on it'* own sometimes, though.

Putting the car into park after driving it and before turning it off seems to make the engine gutter a little, but it picks right back up.

I've perused the internet for hours researching these symptoms, but there is rarely any feedback in regard to what exactly the solution that fixed the problem ended up being.

I'm a college student on a budget- I really need some good leads to get this fixed before it becomes a bigger problem. I've had a few at least semi-car savvy people check it out for me, but they seem to be just as lost for answers as I am.

My check engine light isn't on, but it did come on once briefly while driving. I attempted to have a diagnostic run on the car'* computer a few days ago. I was quickly informed the the car had the older OBD1 system, but for some reason has an OBD2 connector. No one in town has a car diagnostic utility that tests OBD1 and uses an OBD2 connector..... The check engine light has remained off since then.

You mean sometimes you turn the car off with the transmission still in drive? Other than doing it accidentaly I wouldn't reccomend doing that

But anyways it sounds like you have some things clogged up somewhere and a bad crank posistion sensor, someone with a little more knowledge should be able to help you out

If you have to "floor it" for it to start, then I'm thinking that your IAC is either not working, or its stuck closed. This is a valve that opens and closes based on how much air the engine needs when the throttle plate is closed. It'* located on top of the throttle body. Not the flat sensor next to the black hose duct, but behind that one. It'* cylindrical shaped. 2 screws, and it comes out.

At first I thought crank sensor, as soon as you mentioned it would start, that puts crank sensor out of the running.

When it starts hard is there any white smoke out the tailpipes? I assume not, but just checking.

Very much with Mike here..probably a dirty IAC/TB from the sound of it.

Sounds like a dirty throttle body. Remove the IAC and clean it, https://www.gmforum.com/showthread.p...39#post1392359 You may need to remove the throttle body and clean that as well. Guess I better make up a write up on that.

Thank you for that guide, makes it look simple enough for me to do on my own, even.

Is there loctite on the two screws on the IAC?

I believe so, and you might need the special security torx bits, my car had them but some cars I have seen don't

From the factory, they do come with loctite installed. Some have normal philips screws, some have the torx as already mentioned.

I removed the IAC today, and it was a charred, blackened disaster.. Obviously in need of replacement.

I bought a new one and installed it. The car was hesitant on the first try at starting it, but it did start. I turned it off, let it sit for ten minutes, and it fired right up the second time.

I think you guys have solved the problem!! Thank you so much for the input. =)

What a lifesaver.. The last thing I wanted to do was go to a mechanic and shell out hundreds of dollars in pursuit of diagnosing the problem.

Good to hear.