Rough Idle

[mustangapril]

Hi, I'm new here but I have a tech question. Recently, I had to replace a module inside the distributer. After I did that, I had to get it timed, which I did and it ran beautiful for the next 2 days. On the 3rd day, when I started my '94 GT, it began shaking! It continues to do this as long as it is under 1500 rpms.

Today, I checked the hoses and all the hoses seem to be ok. What could be the reason? I've tried googling and asking on other sites but I reach dead ends. My spark plugs should be fine as I bought the high quality premium ones that last 100K 2 years ago. The only thing that I need to maintain are my spark plug wires but could the wires really be causing a rough idle or is it something else?

Thanks

 

[HISSIN50]

Welcome to the boards.

Platinum spark plugs often lead to issues on these cars. Plat is much harder and less conductive than copper (our cars call for copper plugs). I doubt this is your issue however.

Push on all your plug wires (on both ends) to be sure they are seated.

If that doesnt fix it, do a search on how to pull codes. Part of the code pulling process is to run a cylinder balance test (the tests are also noted in repair manuals and instructions for code readers). The CBT is the quickest and most efficient to determine which cylinder(s) is missing. Once you know that, you can examine the spark plug, plug wire, check injector pulsing, and do a compression test on that cylinder if necessary. From start to finish, you can isolate and diagnose the issue in as little as 10 minutes.

One last possible issue is that too much dielectrical grease on the TFI can cause a miss. Too little causes overhaeting, which can cause failure. The chances of either are slight.

Good luck.

 

[mustangapril]

Thanks....I also want to correct myself.....there isn't a module I replaced in the distributer...it was the pickup COIL = ) All these parts are meshing into one......what with frustration and replacing 4 parts......

 

[xr8d302]

The PIP sensor (pick up coil) has been a problem on our 94-95's as long as I can remember. I think pretty much all of us at some point have already had to replace ours.

I second the comment on the platinum spark plugs. If you're running Bosch Platinum 4's, get rid of them while you still can. They'll cause you nothing but issues. Regular autolite 24's will make your stang run like a dream.

Re-examine your timing, although it's not as bad as it could be, it might be slightly off. My dizzy was 180 off when I first replaced my PIP and you would definitely know if yours was the same (car barely stays running)

Ensure none of your spark plug wires are touching exhaust components causing burns and shorts in the system...would make more of a noticeable difference at idle, but you would even notice that on acceleration

Another second for Hissin's comment on checking the spark plugs, might seem like a small thing but you'd be surprised how often they're not securely in place

 

[toyman]

Thanks....I also want to correct myself.....there isn't a module I replaced in the distributer...it was the pickup COIL = ) All these parts are meshing into one......what with frustration and replacing 4 parts......

Am I correct in assuming that you had the stator replaced by someone other than yourself as it must be pressed on? Just wondering if there is a possible link here and having a problem 2 days later.