OK, when I start up my beautiful Acura Integra DA...... the motor vibrates pretty bad to the point where inside I can feel the under dashboard shaking and rattling. After it warms up a bit, it dies down somewhat but still noticeable. It'll vibrate around a certain RPM range when driving but will smooth itself out afterwards. What is wrong with it? Do you think it's the motor mounts?

 

Something is unbalanced. If none of your pulleys are wiggling, then its internal. Missing spark, fuel, compression, etc.... Got some testing to do. Don't run it to long though, if it rods, pistons, or crank shaft, you will just do more damage. Either way, prepare for the worst at that point, doing a motor. At that point, spend the extra money and build one right. Insurance for the money you spend.

 

Did it just start doing this? Is the motor "shaking" while you're looking at it with the hood popped?

 

**** man, are you trying to scare me? You just want to ruin my day for me?

Once it gets running like on the freeway, it runs OK. But it just feels very rough, as if the crankshaft is unbalanced? Or something of that nature that causes it to shake.... you know? If I pop the hood and go under it to rev the motor, it doesn't feel out of the ordinary at all, it's just when I'm inside the car that the under dash vibrates and shakes.

 

What about the balance weights on the clutch?

 

Sounds like your motor mounts are bad