Questions and Answers
Pontiac Bonneville Smells, Drives Funny
Q. Vincent, Hi! Not sure if you can help but here is my problem. I have a 1996 Pontiac Bonneville SE, 3800, automatic, 50,000 miles and fuel injection. The problem is this: Last week I need to drive on the highway for 10 to 12 minutes and noticed that the car didn't want to climb to the speed I was pushing it 55 to 60 mph. I arrived at my hair appointment and it was parked for approximately 1½ hours.
When I left I drove the highway again for approximately 12 to 15 minutes with no problem. The next morning I drove my usual route to work, 12 minutes at 35 to 40 mph, and thought I smelled oil. I notified my husband and he checked the oil the next morning and thought it looked thick and double the amount. I had just had it changed 4/28 and so we drove it down (Saturday 4/17) to the company and they said it was fine.
After we left we were driving 35 to 40 mph and it was acting like it could die at any time at the stop signs. We hurried to Sears and when we got there we smelled a horrible odor. They didn't have time to check it out so we drove it across town to another mechanic and it drove fine and didn't act up.
We then purchased some fuel injection cleaner and placed it in the gas tank. My husband drove around the rest of the day and said it was fine.
Sunday morning I went to the grocery store and it seemed to be driving fine except that when I had my foot on the brake at a stoplight it felt like a heartbeat or thump every now and then. Later in the day I drove around trying to empty out the gas that we put in on Saturday as my husband used the ethanol and I prefer to use regular unleaded but he has been filling the tank when ½ empty for the past two months with 10% ethanol.
I was driving fine until I would reach 50 mph then it acted like it did not want to shift. I got it up to 80 mph 3 or 4 times and it ran fine. Sunday we took it out in the evening to check it again and always around 50 mph it would act like something was stuck and didn't want to shift or felt like it could die. My husband noticed it only did it on flat surface or when climbing a small incline but not when we were going down hill, going down hill was fine.
I do think I should mention that I feel my husband overfills the tank and I have asked him not to do this that when the pump stops I would prefer he stop filling it up instead of trying to make an even dollar amount or pushing on the trunk to try and get as much as he can in.
Someone mentioned on one site that GM said in their area (MN) that there is too much ethanol in their gas. Could this be the problem? Also, we purchased this car in October of 1999 and it has off and on had a horrible smell (Of course, we notice it when we pull into the garage and shut it off). We have replaced the manifold but I am not sure if it was the upper or lower.
We had our mechanic do it as GM charges way to much and these cheap plastic pieces they are pushing on us is totally unfair. Any idea what the problem could be?? I appreciate any advice you can give me. I will need to be on the highway at the end of next month and don't want to risk a breakdown.
Thanks so much Vincent,
NatalieA. What does it smell like, rotten eggs? You may have a intermittent problem with the fuel pressure regulator leaking. This would allow too much fuel to be drawn into the engine and also overheat the catalytic convertor. This should also set a code for rich mixture. Also may have a spark plug wire problem. Pull them off their coils one at a time and see if any corrosion on them. If so, replace them all.
Also replace the fuel filter. The ethanol cleans everything out of the fuel tank and lines and the filters tend to clog up sooner. After all the garbage is out, the fuel filter will not need to be replaced as often.
