PontiacBonnevilleClub.com

Need a little help guys. Any input is appreciated. I have a 2000 Bonny SSEI.
Started to buck, miss(not a dead constant miss), then got the Left Bank Lean code. First time the engine light didn't come on for like 17 miles while it was doing this.
I thought it might be a gas contamination problem as it is intermittent but so can anything electrical be.
You can reset the code and drive it for 7-10 miles and all Ok. Shut it off, go back an hour or so later and its bucking and check engine light comes on. No constant dead miss.
Never has quit and the bucking comes and goes. The shop that has been doing a fine job for me for several years, put a fuel pump(complete unit, sender, etc) and fuel filter on when I took it over there to find the problem.
Picked up the car, started doing it again(a day later) and took it back. Now they are leaning towards the O2's but cant get them to fail when tested. They didnt notice anything strange in the tank and the old filter was pretty bad. Rechecked the new filter again and its clean, but could it be water? They didnt take a gas sample.
Put some drier and additive in the tank last night. This all started with a fill up one night and the next day after filling up, this all started if that has anything to do with it. I have to stop and get the torx to get the MAF sensor out to see if it might be dirty but I cleaned that earlier in the spring(lost the *dang* torx).
No one right now thinks injectors would act like this??
Btw, How many O2 sensors on this car? I only see one from up top(behind rear bank)?
Any input is appreciated. I should have started here first!
I have been on here before and always got help but couldn't log in on my old username(I guess I forgot it)
Thanks much to all!
Danny from Utah

What was the code? P0171? There is only one pre-cat O2 sensor, so the system has no way of knowing whether it is left or right. The most common cause is a vacuum leak. Check all of the vacuum lines both visually, and by spraying carb cleaner around the fittings and check for a change in RPMs. Also spray around the supercharger to lower intake, and lower intake to head gaskets. Pay special attention to the T-fitting to the LIM under the supercharger snout, and the multiport vacuum fitting on top of the supercharger.

Yes, it is that exact code.
Thanks for the tip!!
A couple years ago I had a new GM OEM intake put on it(had coolant in the oil) but I will do the carb spray tonight along with checking the MAF(cleaning it).
That pre cat O2 sensor, is it worth a try if nothing pans out?
I can get one for under 50.00 and put it in.

Thanks again!
Danny

I agree check the vacuum lines, the one under the snout likes to split and will cause a TON of nasty issues, I fought with it for a while before realizing that was my issue.

I wouldnt cheap out on the 02 sensor. ACDelco works the best for these cars, imo.

I went out at lunch and got some Carb cleaner. Sprayed a whole can around all the upper engine, blower, everything real good.
Didnt skip a beat at idle at all. Pulled the MAF and wire looked clean but I am going to clean it tonight to be sure.
Going to use another can tonight at home to check. The O2 pre cat sensor for a GM or Delco is like 40-50.00, so that might be my next step.
What do you all think about water in the gas?? My gut told me that cause I filled up with gas and it started the next day after only 19 miles on the odometer.
It bucks at its worse after a warm restart and pulling out. It will smooth out and if you are very nimble with the pedal, you can almost not detect anything. Car has a lot of boost and power if you get past the first hiccup or two.
Cold morning(Utah, we are finally into winter) you can drive it normal and not feel it. But if you stop, come back after a 15 minute soak or so, you know there is a problem. Starts ok cold or warm.
An O2 is not a lot of money for me to try at this point. But after that, I am lost.
I am going to run this tank down, try some Seafoam and drier and see what happens.
Thanks guys, I really do appreciate your time!
I always gotten help here in the past and Thanks so much!
Danny