UPDATE: Strangely enough, it turned out to be spark plugs. They didn't look like there was anything wrong with 'em. I took 'em out and put'em back in. Finally decided to put in NEW plugs. Problem solved. The shake on mine wasn't too violent. You could just feel it in the seat of your pants at idle, in drive. It would also hesitate on acceleration, just off idle. Then, it would be OK.

Try checking the TPS adjustment. TPS being even 'slightly' out of adjustment can cause idle problems.

Mike in AR