Its been a LONG time since I have posted anything on here, school and work keeps me occupied I guess.

Anyways, I have been having an ongoing problem since probably about the start of this year, the car will intermittently run/idle rough, almost like it missing a cylinder. There isn't really anything that causes it that I can tell, but has the problem mostly after starting when the car has been sitting over the night/day.

When the car started stalling, I took the car into the shop and the fuel pump tested bad so I had it replaced, and it hasn't stalled since, but still runs rough at times. I replaced the plugs,wires, fuel and air filter a couple weeks ago, and no difference. No CEL, no codes other than trans code that comes and goes.

Any help is much appreciated, I really want to stomp this problem out. Hope all of this makes sense.

replace the iac ( idle air contrl esenor) that should do the trick..

A rough idle is often caused by a vacuum leak. Have you checked all of the vacuum hoses and fittings? Before replacing anything, you may want to do a good throttle body and MAF cleaning, including the IAC and IAC passages. The procedure is here in techinfo.
http://www.bonnevilleclub.com/forum/...e=article&k=64

The most overlooked and most likely culprits (if it IS a vac line) are at the vac. canister near the fuse and relay center, and the cruise control signal line. Either a dab of silicone (and I do mean a dab) on the ends of the line, or the smallest wireties you can find will keep them where they are supposed to be.

Personally I would not recommend the silicone as you will have to clean if off later and wonder if it'* cured before starting the vehicle. Wire ties..well..that'* a bandaid that I myself have used.

The best way to fix vacuum lines is to replace them. Autoparts stores stock line in many sizes.. get a foot or so of each size that you think you need and replace them. This way if they are old and cracked, you fix the whole piece of tubing.

Thanks for the responses, but I have a question.

Would these problems just cause a rough idle, because it will be rough under WOT also?

Also, when I changed the plugs and wires, I pulled one of the wires off of the spark plug and started the car and it sounded and felt like it does when it runs rough.. if that helps any.

In that case I would be looking for a bad plug. It is possible that you dropped or cracked a plug?

Not that I recall. I am going clean the throttle body, MAF, and IAC tomorrow and see if that fixes it.

Could hot weather make this problem worse? After sitting outside at work it seems to be worse than when I start it up after sitting in the garage over night.

The shop I took it to told me to bring it in when it is running rough but the problem is so intermittent that it happens at anytime while im driving.

Thanks again for the help.