I have a 1999 nissan altima 2.4 L that runs rough at all times to the extreme that the hood vibrates. I have changed the cap plugs and the motor mount. Any suggestions?

Did you install the same NGK plugs that originally came in the car?

Have you checked for any codes?

The Ignition Control Module (ICM), located inside the distributor, may be bad. I recommend replacing them every 120,000 miles or 10 years, whichever comes first. They are very problematic components. If you installed the proper plugs, the problem is likely distributor related. My bet is the ICM is failing. You may find it easier to install a new distributor.

Are the spark plug wires on in the correct order, are they supplying current to the spark plugs, sounds like it's misfiring!