Need opinions on engine problem.

[sl03gt]

Have a 94 GT that has a shake in the motor. Has all new plugs, wires, cap, rotor, clutch, and balancer. The idle does not surge but the motor shakes like it has a miss that can also be felt in the shifter. I got the car for cheap and the person that had the car before didn't have the O2 sensors hooked up so I'm not sure if he might of burnt out an valve seat. Now to the root of my question when you listen to the exhaust there is a flutter every fourth pulse on the drivers side. Does that sound like a bad valve or seat? Any body else ever have this problem?

 

[blazrrr]

My car does the same thing. From what I have read, this is a semi-normal occurance.

 

[sl03gt]

I had a 95 vert that never did this. The vibration gets worse with rpm. The tail pipes shake, this really sucks.

 

[1TallMF]

Have you looked at your harmonic balancer? Get under the car and look for any of the rubber that might be protruding out from between the center hub and the outer ring. Its very comon for the rubber to work its way loose over time and cause the outer ring to slip, which puts it out of balance. If the harmonic balancer looks okay, I'd do a compression test to see if any of the cylinders are not holding compression like they should. But even before doing this, you can perform a cylinder balance test with a code reader, and this might help in pinpointing the problem cylinder(s).