Hi I have a 1994 nissan sentra that gives avery rough idling. When driving it goes away but once in idle the whole car shakes. I did a tune-up not long ago and was thinking it might be the engine mount but the shaking seems to come from the exhaustwhich wwas put on after I got the car. The engine idles at normal rpm. Can you tell how to fix this and what maybe causing it?

How long ago was the "tune up" and what was actually done?
Did you do it to fix this problem? Did it help?

Check for the ultimate cause of the rough idle, whether it's caused by ignition or fuel, or a vacuum leak.

I had changed all ignition components, spark plugs, ignition coils, cable. I also changed air intake to a spectre performance intake. But I am thinking maybe the engine mount bushings are worn after seeing a lot of shaking coming from it.

Check the mass airflow sensor ad clean the idle air control valve as well as the entire throttle body

i had changed all ignition components, spark plugs, ignition coils, cable. i also changed air intake to a spectre performance intake. but i am thinking maybe the engine mount bushings are worn after seeing alot of shaking coming from it.

Did all this start before or after these modifications?