I am a 4.6L guy but my buddy has a 94 5.0L. His engine shakes very bad and we can not figure it out. We thought motor mounts so we changed them. They were broken but no change in the vibration. Installed all new ignition componets, except distributer, still no change. I found out he had a dead cyl in #5 by taking a spray bottle with a steady stream and spraying all of the exhaust manifold tubes to see which one the water didn't disapear fast. So we changed out that injector and cyl came back to life but still no change. Rechecked the timing and its good. The only thing left is the balancer but I want to hear what you guys say before he goes and throws down $60 on a new one.

The car shakes very bad at idle and speeds up with the rpm's.

 

sounds like the balancer to me

 

it is the balancer....spend the 60 bucks.

 

My 87 GT that I just bought does this at high revs in 2nd and 3rd gear as well.

Let me know if this fixes the issue.

Swirl

 

Yup, balancer.