Ok, Like I said no codes.

Already replaced wires with the magna cores, running ngk iridiums.

-no vacuum leak
-no arcing
-compression test yielded no valves sticking



Getting really sick of this truck. She's never failed me but dear lord the little gremlins are enough to kill you.

The scanner is showing maybe a problem with 1 2 and 8 cylinders when we watch the data while she we running. Any ideas?

 

Are you sure it is a misfire and not just a normal "stumble"?

 

Normal stumble? I'm starting to think it might be a hermonic imbalance in the motor, but then shouldn't it get worse as the vehicle revs.

 

All engines have a "stumble" at a hot idle, usually not noticeable but a broken or worn motor mount or like you said a bad harmonic balancer can make it seem worse that it is.

If your check engine light works and you are not getting any codes then there is no problem.
If there were a problem it should show up within 400 miles, the worse the problem the sooner it sets off the check engine light.

 

When you say no vaccuum leak you mean you put a vacuum gauge on the manifold and got 16-22 inches of vac that didn't slowly drop or oscilate... just steady?

 

To check the vac leak we sprayed carb cleaner arount the intake manifold and listened to the engine to see if there is a raise in idle

 

A vac gauge can help you see changes quicker, before code readers they were a popular diagnostic tool that has had to stand in the shadows lately.