Help! Weird Sputtering on 2000; only when warm.
 

Hey guys please help,

This is my first post though I have been reading the forum for a while trying to figure out what's wrong with my wife's bonne. It's a 2000 with about 150k on it.

It runs and drives like a champ until its warm; then it starts sputtering and loosing power. It feels like it is running out of gas and sometimes the tach drops to zero but it still drives (kind of). I changed the fuel filter but it didn't help. It threw a code for a cam sensor and I changed that and it didn't help either. That was the only code and it only came up a couple times.

Also, it seemed to start going bad kind of slowly. At first it would only sputter for a second on the interstate when going over 70. Then it started doing it a slower speeds. Now, as soon it warms up, with the temp gauge right in the middle (doesn't over heat), it does it at any speed when accelerating. No problems starting at all. When the tach drops to 0, you can pull over and restart it and the tach resets.

Nobody around here really wants to work on it so I am kind of stuck. I could have it towed to GM but they want a fortune. Any help you could give would be INCREDIBLY appreciated. I'm not much of a mechanic but with the help of YouTube I have been able to figure out how to do the simple stuff. :) I'm hoping someone has had a similar problem and can help me figure it out. Thanks in advance!

I'd take some carb/intake clearer and spray your vacumme hoses. You might have a leak there. Also this could be a LIM situation. Does your exhaust smell sweet after your car warms up?

Test your coils. I suspect you have a bad one, but only when it's warmed up.

I just youtubed a coil test :) in which you use a little piece of vacuum hose to test the spark. Will that work for this? Also I haven't noticed any sweet smell.

I will look up how to check vacuum lines next and try both of those first.

You guys are fast! Thanks again!

There is a coil test in the tech info section here off the main menu. Just look in testing.

I think it is the middle coil! :) I followed the guide and it read higher on the top terminals than the other two and on the bottom connections it read 0.0. I am going to go grab a new one after lunch and I will let you know how it goes. Thanks again!!!!

Becareful when loosening and tightening the bolts to the coil. They are small and easily broken if not careful. Also be sure to put some dieletric grease on the bottom and top terminals to protect from moisture.

Yep, that one is dead. As mentioned, be careful. The bolts go in to aluminum and strip easy. Just snug.

I had autozone test the coil too and they also determined it was bad. I swapped it out and drove around to it warmed up. It seemed to run a little bit better but when it got hot it started sputtering again. I checked the ohms on the top of the coils again and the middle one was still a little higher (9.x). Could that mean the ICM? I also saw some white smoke when I first started it and kind of thought it smelt kind of sweet; but I really don't know how to tell. I'm not a good judge of the sweetness level. :)

Any ideas on what to try next?

Pull the spark plugs and inspect them. Look for any differences in the tips. All shoudl be clean with a slight gray color.