Vibration idle and cursing

[pieceofchevy]

it is a gmc Gods mechanical curse. i own one and it is a constant battle to fix daily. but it is a 91 and it was abused before i got it. check out your harmonic balancer, it might be bad or loose.

 

[Schurkey]

Thinking my motor mounts are bad I get this low vibration when idling and driving down the road. How hard are they to change out any other thoughts what I could be

OP, start at the beginning and describe the problem completely then proof read before you post.

God bless you.

The title says "cursing" which I take for cruising since your initial post said a low vibration "driving down the road". Later you said it makes a "think" sound going into reverse. Conflicting info or multiple problems we may need to look at separately. 2/3 of your info makes me think U joints the other 1/3 does not.
You never mentioned misfire but others did.
We can help if you are a little more clear on the problem.

U joint I would bet.

Making an assumption due to insufficient description of the problem. He says "when idling AND driving down the road". To me, he's saying it does this while the engine is running but the vehicle is STOPPED, and when moving under power.

That's not a U-joint problem, 'cause the U-joints aren't moving when the vehicle is stopped.

But of course, I'm making assumptions and that's rarely a good thing.