Intermittent dual misfires=head scratcher

[Viggen]

Hey All -

Boy, am I in a pickle.......

About 2 weeks ago, I started to feel a rumbling vibration and a nasty sound coming from the engine bay. A couple of days ago, the PCM finally threw up some codes for me. I have misfires in cylinder 2 & 6, so I figured it was easy to fix.

Sent it to Ford, they have spent (at current time) 5 hours trying to diagnose the cause. The problem is it has become intermittent, and the gamut of tests they have run have come back clean and working well.

Theorizing, the Ford techs might think it has to do with the performance tune I have running in it. I talked to my guy, and I tend to agree with him, this is not the cause or else it would have popped up a lot sooner. I told them not to reflash also.

You would think Ford could find their own problems.

To say the least, I told them to stay on it, but we are getting to an impasse where they might start swapping out everything and going from there. Lots of $$$$$ if you can imagine.

Anyone have a problem similar to this? I assume they ran a compression check, all injectors are fine, coil pack swapped out, plugs seem good, etc. NOTHING!!!

For information, I have an ASP UDP, CAI, TB spacer, and Accel coil pack and wires along with a more then reputable performance tune. The tune and udp have been run for almost 3 months, the coil pack since 9/07 and the intake and wires since 5/06. This pig only has 43000 miles on it.

Any thoughts would be appreciated, and I know it is hard to diagnose intermittent misfires alone, more without being in front of the truck.

THANKS

 

[jah81592]

This is interesting. I was never aware of the aftermarket coil pack on the vehicle. Why doesn't Ford run the primary and secondary tests on the coil. I am not saying that the coil is the problem but it would be a start. Especially when this is the source computer determines the misfire from. This information would've been nice to know when you contacted me.-j

 

[Viggen]

The ford techs swapped out my Accel pack with the stock I had....it continued doing the same thing. Now they think it's the crank pulley, and the familiar wobble, again. They are putting the stock pulley back on and seeing where it goes from there.

 

[heatxcape]

I had a similiar problem and spent lots of $$ and time....teh culprit was bad wires. change the wires with some from Ford and i am sure it will help. I changed mine twice...aftermarket from Summit, but had to go back to the Ford brand.