zap387
Active Member
- Joined
- Jun 23, 2013
- Location
- Belmont, NC
I have a 2000 wrangler with a 4 cylinder it was swapped by previous owner with a straight 6 it has about 108,000 miles and is currently having issues and I am out of ideas. Was running good until now.
problem: rpms bounce around acts like it’s going to die when idling sounds like a muscle car with a cam when it acts up. Sometimes rpm hits 0 almost dies then jumps back to life jumps to about 1100 rpm then drops back down to about 700 and runs normal for a while. A while meaning a few days maybe then has issues again then it clears up and the cycle repeats.
I've tested all the sensors including:
Changed out the throttle position sensor with new one
Changed out the idle air control valve on throttle body
Cleaned throttle body with sensor safe tb cleaner
Changed plugs with new iridium’s from autolite issue was occurring before plug change swapped plugs back to copper champions to check still has same issue.
O2 sensors working in spec verified by my scan tool and jeep dealership scanner and offroad shop scanner
Tested for vacuum leaks by an off-road shop and myself carb cleaner test and it passed
Also when it acts up short term fuel trim jumps from -2 to about -35 PCM is trying to lean out the jeep no idea why only happens when it idles rough.
Fuel pressure test was good injectors are good and ran injector cleaner just in case
Passed compression/ leak down test.
Checked all ground wires and they are clean jeeps from the south tested for ground with digital multimeter
No engine light, no codes present at anytime verified with scan tool with live stream and verified by dealer
Issue happens in open loop and closed loop at random times, so its not a heat soak issue.
checked wiring harness for chaffing like behind the motor, but all is good.
A good local 4x4 shop couldn't figure it out and neither can the jeep dealer expert! anyone have any ideas left? Its my daily driver and I don't know what else to do. Also I am not a mechanic, and Jeeps still at dealership so I cant do any more testing for a few days. Also I have searched the forums, and the internet.
problem: rpms bounce around acts like it’s going to die when idling sounds like a muscle car with a cam when it acts up. Sometimes rpm hits 0 almost dies then jumps back to life jumps to about 1100 rpm then drops back down to about 700 and runs normal for a while. A while meaning a few days maybe then has issues again then it clears up and the cycle repeats.
I've tested all the sensors including:
Changed out the throttle position sensor with new one
Changed out the idle air control valve on throttle body
Cleaned throttle body with sensor safe tb cleaner
Changed plugs with new iridium’s from autolite issue was occurring before plug change swapped plugs back to copper champions to check still has same issue.
O2 sensors working in spec verified by my scan tool and jeep dealership scanner and offroad shop scanner
Tested for vacuum leaks by an off-road shop and myself carb cleaner test and it passed
Also when it acts up short term fuel trim jumps from -2 to about -35 PCM is trying to lean out the jeep no idea why only happens when it idles rough.
Fuel pressure test was good injectors are good and ran injector cleaner just in case
Passed compression/ leak down test.
Checked all ground wires and they are clean jeeps from the south tested for ground with digital multimeter
No engine light, no codes present at anytime verified with scan tool with live stream and verified by dealer
Issue happens in open loop and closed loop at random times, so its not a heat soak issue.
checked wiring harness for chaffing like behind the motor, but all is good.
A good local 4x4 shop couldn't figure it out and neither can the jeep dealer expert! anyone have any ideas left? Its my daily driver and I don't know what else to do. Also I am not a mechanic, and Jeeps still at dealership so I cant do any more testing for a few days. Also I have searched the forums, and the internet.
