1. 97 tj 2.5 backfiring, cutting out, tach jumping around

    Hello everyone, New to the forum. I've read lot of post on this issue and still can't figure it out. It starts and idles fine. When I drive it after it gets warm it starts backfiring and cutting out under A load. It will rev up just fine but just cruising it has this problem. I have replace both 02 sensors with NTK's crank sensor with mopar, cam sensor/coil pickup with mopar and no luck. Also have checked most of the grounds I can see. Cap and rotor plugs and wires all good. Could A bad battery do this? Or is the common places to check wiring harness for damage?

  2. #2
    Join Date
    Feb 2009
    Location
    Dayton Ohio Area
    Posts
    5,742

    97 tj 2.5 backfiring, cutting out, tach jumping around

    There is a few things this could be.
    If it is the same pedal position -TPS
    If after warming up either O2 sensor or temp sending unit. Not sure if 97 has two temp sensors. one for the PCM and one for the display.
    Easy test is to unplug the upstream O2 sensors and tie them up and see if it hesitates the same.
    Then reconnect and do the same for the temp sensor.
    If the issue no longer exists after unplugging you may have found the issue.
    You will throw codes so reset them after testing is done.


    Another could be a vacuum leak.


    PS your RPMs drop or get erratic when this happens.??? Auto or manual trans?


    Never look down on anyone unless you are helping them up - Jesse Jackson
    Last edited by JPNinPA; 12-05-2020 at 04:29 PM.
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

  3. #3
    Join Date
    Feb 2009
    Location
    Dayton Ohio Area
    Posts
    5,742

    Re: 97 tj 2.5 backfiring, cutting out, tach jumping around

    Did you fix this?


    Never look down on anyone unless you are helping them up - Jesse Jackson
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

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