The_97_Sport
NAXJA Forum User
- Location
- Michigan
:new:
I have been struggling with my 97 XJ sport 4.0L for a very long time now.
the problem does not seem to change no matter what i do.
Here's the symptoms:
1.when at idle it will seem as if its ok, but then it will bog down and jump right up again to normal and repeat, but it will not stall. sometimes, the idle will become very rough, then it will be nice and smooth and repeat; all of these symptoms are consistent and in no particular order.
2. when accelerating regardless of RPM, speed, or engine temp. it will sporadically bog down, hesitate, then all of the sudden accelerate at full power again. this symptom is also consistent.
3. check engine light is on with the following codes:
P1391: CKP or CMP Sensor Signal Intermittent
P0135: O2 (B1S1) Heater Circuit
P0141: O2 (B1S2) Heater Circuit
after scanning the OBDII it seemed straight forward so i replaced the cranksahft position sensor with a genuine MOPAR sensor from the dealer as well as the precat O2 sensor with a OEM NTK sensor. i did not replace the post cat O2 because i am making the assumption the allegedly bad precat O2
was giving the post cat O2 an incorrect reading.
anyway, after replacing these parts and clearing the computer, the same codes still came up and the problem still existed.
i did some further research online and found out it could be the PCM causing false codes so i opened up my PCM and found 2 broken pieces of a circuit floating around inside so IT HAD TO BE THE PROBLEM right?? WRONG.
replaced the PCM with a rebuilt and the problem still persist. and the exact same codes come up from the OBDII.
at this point im ready to give up and realized i never checked my MAP sensor so i started it up, unplugged the sensor and the jeep still ran, but it wouldnt rev past around 3k RPM, but my understanding is when the MAP sensor is unplugged it should not run at all so i replaced the MAP sensor and still no change; the problem still persists and the engine light is still on, but i have not had it re-scanned yet.
anyway, i am pretty burnt out and i'm afraid i may be missing something obvious.
any help and opinions for next steps would be greatly appreciated.
for now, my next steps:
1. scan the engine light again check to see if same codes come up after replacing the MAP sensor.
I have been struggling with my 97 XJ sport 4.0L for a very long time now.
the problem does not seem to change no matter what i do.
Here's the symptoms:
1.when at idle it will seem as if its ok, but then it will bog down and jump right up again to normal and repeat, but it will not stall. sometimes, the idle will become very rough, then it will be nice and smooth and repeat; all of these symptoms are consistent and in no particular order.
2. when accelerating regardless of RPM, speed, or engine temp. it will sporadically bog down, hesitate, then all of the sudden accelerate at full power again. this symptom is also consistent.
3. check engine light is on with the following codes:
P1391: CKP or CMP Sensor Signal Intermittent
P0135: O2 (B1S1) Heater Circuit
P0141: O2 (B1S2) Heater Circuit
after scanning the OBDII it seemed straight forward so i replaced the cranksahft position sensor with a genuine MOPAR sensor from the dealer as well as the precat O2 sensor with a OEM NTK sensor. i did not replace the post cat O2 because i am making the assumption the allegedly bad precat O2
was giving the post cat O2 an incorrect reading.
anyway, after replacing these parts and clearing the computer, the same codes still came up and the problem still existed.
i did some further research online and found out it could be the PCM causing false codes so i opened up my PCM and found 2 broken pieces of a circuit floating around inside so IT HAD TO BE THE PROBLEM right?? WRONG.
replaced the PCM with a rebuilt and the problem still persist. and the exact same codes come up from the OBDII.
at this point im ready to give up and realized i never checked my MAP sensor so i started it up, unplugged the sensor and the jeep still ran, but it wouldnt rev past around 3k RPM, but my understanding is when the MAP sensor is unplugged it should not run at all so i replaced the MAP sensor and still no change; the problem still persists and the engine light is still on, but i have not had it re-scanned yet.
anyway, i am pretty burnt out and i'm afraid i may be missing something obvious.
any help and opinions for next steps would be greatly appreciated.
for now, my next steps:
1. scan the engine light again check to see if same codes come up after replacing the MAP sensor.