Hello all, I have a 2002 Grand Cherokee with the 4.7 HO engine. Bought it as is with 168,000 miles on it. Starting up in the morning it revs up to over 2 grand then down to 100 then jumps all over. After it warms up it settles out around 700 but keeps jumping up once in a while.
Thanks for any suggestions. Dealer charged 300 bucks and change the right manifold o2 sensor but did no good for the repair.