93 Grand Prix 3.1L SE - Engine coughs - 10 MPG - Gutless - Run rough

if you can get the computer codes,that may help. but a common problem like this is caused by temp sensor. it tells computer how hot/cold engine is.and the oxegen sensor is another culprit that causes this problem. you can get at parts house to see what it looks like. auto zone can pull the codes for you for free ,that may help. lucas

Bad plug wires.

Hi there Darrell,

Looks like we are experiencing the same problems. I presently own a 98' Grand Prix SE with a 3.1L engine too... and I've been trying to figure this problem out for the past few months.

This is what I've done, (1) changed the spark plugs and the wires, (2) checked the Mass Air flow sensor, (3) even changed one of the ignition coils since I managed to figure out that it is the middle cylinder in the rear block that was causing the problem, but the ignition coils were not the source of the problem, it came back again, (4) and I'm presently running some injector cleaner in my fuel tanks... hoping that it's clogged injectors that are the source of the problem. The injector cleaner helps to ease the jerking a bit... but the problem is still there. I'm really stumped by this issue... so if anyone got a solution to this, I'm sure glad to find out.

I'll try to looking up on the forums on how to determine a faulty O2 sensor... and I think it the source of the problem is a sensor... since it's so erratic.... like you said, one time is goes crazy, and the next... it's running smoothly.

I've checked most forums.. and your present situation is the closest that is to mine.

Cheers, Tantor