still cant figure it out?????

[stevefx19]

Alright, I bought my mothers 94 Bonneville off of her 3 months ago. I've been working on it ever since then to get it running better. Last summer it ran like a champ, especially with the gas mileage. After this last winter it was running like crap. I put new spark plugs and wires on it, air filter, fuel filter, and an oil change. THat helped a little bit. Then I started using fuel injector cleaner, that helped a tiny bit. Then I replaced my tranny gasket and filter and fluid. That helped a whole lot. It runs way better but still eats gas and when I accelerate the exhaust sound really bad and feels like it still dont have enough power. What should I do cause I know that exhaust has never sounded like that????

[LMP]

The 3800 computer parameters that are programmed for the adjustment of fuel mixture in relation to temperature are very badly set. They are OK at normal operation temperature, but when cold, the mixture is set very..and I mean VERY rich to ensure the engine fires up...with the assumption that this condition will not last for long and it will fall into the "normal" temperature curve soon. This is not the case in short winter trips, and this translates in a very evident rich mixture smell and huge fuel consumption in cold climates. On the open road with long trips, it falls back into a normal bracket for winter driving.
All I have described here is "expected".
I have corrected that situation by introducing a "correction" in the temperature feed to the computer and this has translated in enormous fuel savings in winter driving.
I do not know if what you describe exceeds that description. One good thing to do to collect some cues would be to have the codes read. I think this '94 bonneville was already an OBD2 so it needs a scanner.
That would provide some indications to start with.
BTW, what mileage is the engine? There have been some reports of timing chain that have slipped a tooth or 2....but this needs a lot of mileage.

[randman1]

It sounds like the normal tune up items were helping. Did you change the O2 sensor? What about a clogged cat?

[stevefx19]

My car has 113000 miles on it. I think I am going to have the codes read on it. Also there might be a hole in the exhaust pipe between the cat. converter and where it attaches to the engine cause thats where it sounds like it is coming from. Could that be the reason why it is messing up???