Rough Idle..... No CEL/Wrench

[Flag Gibby]

Great to hear that your MPG went up, at least you have gotten something for all your efforts. I would try to track down where that black soot is coming from since there really isn't much else you can do.

 

[batesfusion]

Update... Dealer had no idea what it was. Mechanics says "it's normal on the 4.0"..... Jesus, really? Would you sell a car that vibrated like that? And tell people it's normal.
They ran their fuel system cleaner through it. Didn't help. I brought it home swapped out the harmonic balancer. Problem fixed.

Harmonic balancer looked fine, felt fine but it wasn't.