Wiley Coyote
NAXJA Forum User
- Location
- Anchorage, AK
I’ve been working on a problem with my Jeep for almost a month now and it’s driving me nuts. It’s a ’91 Cherokee 4.0L, AW4 tranny, 4WD. It idles rough, like its randomly dropping a cylinder. It appears to get worse as the engine gets hotter. It stumbles about once every two or three minutes. At part throttle it runs fine. During hard acceleration or under load (2800 rpm and above) it starts cutting out again badly and backfires. The spark plugs are getting fire, the air filter is clean and unobstructed and the injectors check good with an ohmmeter. So far I’ve replaced the cap, rotor, spark plugs and wires, MAP, TPS, O2 sensor, Cat, header, cleaned the inside of the valve cover and PCV front and rear (new ones installed with new vacuum lines) and idle air motor. The CPS was replaced 3 months ago (before all of this started). None of it has made any difference. Any suggestions?