My buddy just bought a 98' TJ 4.0L with 61k on the clock. He is having these problems: When Jeep is cold it idles very rough and sometimes surges like it is about to stall...it almost sounds like my 89' Mustang cammin'...lol also when driving sometimes at low rpm the Jeep will sputter and backfire and come close to stalling, it is almost like hitting rev-limiter. Both problems go away once the Jeep warms up. I already took the T-body off and cleaned it, also changed the plugs and gave the Jeep a full tune-up. Any ideas?? O2's fuel filter? Any help would be greatly appreciated.
Whoops, rough idle...not rought.