Hi Scotty, i have a 2002 grand cherokee wj 4.7 v8, on idle the engine shakes a little and rpm ups and down between 600-700. i have changed the tps, idle valve and map sensor, cleaned the throttle body, still does that, what could it be? thanks

vacuum leaks, try this video https://www.youtube.com/watch?v=zMok2y05jNE

thanks, will try that cigar !!