performance problems

[ahazuarus]

Hey guy, got a question. I am curious to see if anyone on this site can help me with this problem. I have a '98 Olds Acheiva (3100) with performance problems.

Basically... I have intermittent misfiring. Replacing the fuel filter nearly doubled my engine performance. that was a couple of moths ago, now I have only slightly better performance.

When I say intermittent, that is exactly what I mean, it will cough and sputter ever so slightly anywhere between point A and point B and never the same time or place twice.

Maintenance:

I change oil every 4000 miles

Often use injector cleaner (doesnt help)

changed plugs and wires recently (no improvement)

I know the '97 Olds Acheiva had several electrical problems. My car, however, appears to have none of these.

Somebody please help give me some ideas to try. I have been experiencing this problem for over 3 years, no ones suggestions have helped at all. The fuel filter was my idea and so far its the only thing that has improved anything.

And that doesn't help me because I have no idea what I am doing! Please help!

[robertisaar]

maybe the fuel pump is shot?

[TiredGXP]

You said that replacing the fuel filter doubled performance. Sounds like you're saying that performance has been decreasing since that time.

Have you considered checking out the new fuel filter to see if it's clogged? Maybe you have a bunch of crap in the gas tank that's clogged another one.

[no_doz]

did you notice what was clogging the first one? id say its fuel filter or your pump is shot.

you might have rust in your gas tank that is getting built up in the fuel filter

[robertisaar]

you know whats funny? the monte had the original filter in it from the factory up until about 4K miles ago(and was an absolute bitch to remove), and the only reason i changed it then was because i figured i might get something out of it(power/mileage wise).... nothing.

thats even after 186K miles and this is the second gas tank, the first one had a rust hole at about 145K... yet the filter never clogged. original pump too.

i guess what i'm saying is that if your filter already got clogged once with something, it will probably happen again...