Hi,
I have a 2000 XJ with the federal emissions package (2 O2 sensors).
Sometimes, but now always, when idling at a stop light, I will get a very rough idle, where I need to keep my foot on the gas to keep it from stalling.
When I give it gas during the fits of rough idle, there is a very, very sluggish throttle response, and it will surge/pulse.
Also, in general, when idling RPM's fluctuate slightly, maybe 50-60 rpm. The Jeep will idle fine all day, and randomly start acting up.
Here's what I've done to try to diagnose it so far:
Looking at my scanner when running, I'm not seeing any weird MAP values, so I'm assuming my MAP sensor is good. I don't know how to test the coil rail.
I don't think it's a vapor lock issue, since I don't have a problem restarting the jeep after shutting it off, and I don't have any pre-cats with the federal emissions package. Also, this idling issue can happen with the hood completely open.
The only codes I have is for a bad downstream O2 sensor and missing battery temp sensor. I don't believe either of those have anything to do with how the engine runs.
Fuel Trims:
Does anyone have any idea?
I have a 2000 XJ with the federal emissions package (2 O2 sensors).
Sometimes, but now always, when idling at a stop light, I will get a very rough idle, where I need to keep my foot on the gas to keep it from stalling.
When I give it gas during the fits of rough idle, there is a very, very sluggish throttle response, and it will surge/pulse.
Also, in general, when idling RPM's fluctuate slightly, maybe 50-60 rpm. The Jeep will idle fine all day, and randomly start acting up.
Here's what I've done to try to diagnose it so far:
- NEW IAC
- New Mopar TPS
- New NTK Upstream O2 sensor
- Cleaned throttle body
- New NTK copper plugs
- New TUPY cylinder head (had this problem before and after the new cylinder head)
- Smoke tested for Vacuum leaks - no leaks
- Fuel Pressure Test - Fuel pressure tested good during bad idle
- New Coil Rail
- Multi-meter tested all grounds, battery terminals are new, soldered on copper lugs on cables.
Looking at my scanner when running, I'm not seeing any weird MAP values, so I'm assuming my MAP sensor is good. I don't know how to test the coil rail.
I don't think it's a vapor lock issue, since I don't have a problem restarting the jeep after shutting it off, and I don't have any pre-cats with the federal emissions package. Also, this idling issue can happen with the hood completely open.
The only codes I have is for a bad downstream O2 sensor and missing battery temp sensor. I don't believe either of those have anything to do with how the engine runs.
Fuel Trims:
- I did notice that I have some rich fuel trims during these fits. I'll attach a picture of these
- LTFT- 33.59
- STFT- -27.34
- Due to the fuel trims, I'm thinking one or more of my injectors are intermittently getting stuck open, however; I'm not sure how to test that.
Does anyone have any idea?
