theway146

This miss happens nearly all the time in 3rd gear, but only from maybe 1200 to 1400 rpms. It happens at the same rpm in 4th gear, but not as much. I can cruise all day long at 70mph/2200rpm without any hiccups. It's an automatic '01 GT (97k) with just a K&N filter in the stock box and a flowmaster exhaust; no other mods. I just replaced all the plugs and have done two treatments of Lucas fuel injector cleaner. The miss has remained the same throughout.

The car starts fine, idles near perfect, and feels strong on hard acceleration.

The miss can be described as small "hiccups" in the power delivery at those rpms and there is a distinct fluxuation in the rpms when it is happening. There is no detonation or any other weird noises, ticks, or the such. It happens at light throttle.

Thanks for your help!

samsu402

I almost had the same problem with my car. Mine would never do it at WOT throttle. Its a small hicup or hesitation when your driving normally. And you might notice when it happens that your engine light starts to flash. When you pulled your plug, were any of them really wet with fuel? Are you throwing a code? If you are,check to see what cylinder is mis-firing and a use a deductive approach from there.

You changed the plugs, so the next thing to do would be to change the coil of the cylinder that is mis-firing. Keep us posted.

I fixed mine yesterday and it runs amazing. It was the coil in cylinder two.

Good luck

theway146

Thanks dude, I bet it is a coil.

Although, I am not throwing any codes and the check engine light does not blink. So, how in the world could I diagnose which one(s)??? Or does that mean it could be something else??

When I pulled the plugs there was burnt fuel on them, but that is a whole different story. [Dealer in GA pulled the fuel mgmt relay/plug on an unrelated repair and the injectors were spraying extra fuel cause they forget to plug it back in! ]. https://mustangforums.com/forum/4-6l-1996-2004-modular-mustang/476589-help-car-is-hijacked-by-out-of-state-dealer-pcm-question.html

The engine miss was there in the same way before the dealer screw up. I also should note that I have cleaned the maf sensors with that special cleaner, and cleaned the throttle body (also the K&N filter is brand new)...