1. Hard Start, rough idle, chugs

    My 89 Cherokee has had a hard start and rough idle since I started driving it about a month ago. Today it started chugging real hard. It's doesn't die, but when you hit the gas the RPMs move up and it lurches forward, but doesn't move very far.

    The hard start is intermittent. It's hardest on cold starts, and will generally start pretty easy if it's been running.
    This morning it started pretty easy for having sat all night. I backed out if the driveway just fine, got about 3 houses down the road and it started chugging. I shut it off, sprayed some starter fluid and it started right up, drove with no chug for about a block and a half, and started chugging again.

    In the last month I have done:
    Plugs/wires
    Cap/rotor and ignition coil
    Fuel filter
    Fuel pump
    Fuel Pressure Regulator
    All vacuum hoses in the RENIX
    New air filter (and replaced the top of the air filter box)
    Crankcase Position Sensor
    And I've run IsoHeet and Seafoam through the tank.


    Update: I checked the pressure it's staying stable around 31. While checking fuel pressure it seemed to be running fine, so I drove it around an empty parking like for 15 or so minutes, seemed fine. Then I drove it to the parts store (about a mile drive) and on the way home it started giving a sporadic chug here and there, but never died or stalled.
    Last edited by Buffokill; 07-13-2020 at 11:48 AM. Reason: Update

  2. Re: Hard Start, rough idle, chugs

    Spark plugs are responsible for igniting the fuel in the combustion chamber. If they are not working correctly or are dirty they don't ignite the fuel cleanly and the car can misfire or sputter.

  3. #3
    Join Date
    Feb 2009
    Location
    Dayton Ohio Area
    Posts
    5,649

    Re: Hard Start, rough idle, chugs

    Does it ever clear up? Once the engines heats up?
    I always start with check the battery and clean the grounds at the battery engine and chassis.


    Regards,
    JPNinPA

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

  4. #4
    Join Date
    Feb 2009
    Location
    Dayton Ohio Area
    Posts
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    Re: Hard Start, rough idle, chugs

    Check fuel pressure.



    Regards,
    JPNinPA

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

  5. Re: Hard Start, rough idle, chugs

    You might take a look at the idle air solenoid. They can cause trouble as described.


    Sent from my iPad using Jeepz.com mobile app

  6. #6

    Re: Hard Start, rough idle, chugs

    Stays stable around 31.

  7. #7

    Re: Hard Start, rough idle, chugs

    When it heats up it still has rough idle. I've driven it a couple miles since it started doing this and it felt fine for the first mile, but towards the end of the drive the chug was getting worse.
    It hasn't done that full chug/lurch that it did the other day.

  8. #8
    Join Date
    Feb 2009
    Location
    Dayton Ohio Area
    Posts
    5,649

    Hard Start, rough idle, chugs

    If only when ideling look at cleaning the IAC as mentioned.
    If it is both running and idling there may be other items worth looking at. The temp sending unit for the pcm and the upper O2 sensor and timing. What RPM do you idle at?

    Note from a cold start either how long and what temp the chugging starts.


    Never look down on anyone unless you are helping them up - Jesse Jackson
    Last edited by JPNinPA; 07-14-2020 at 11:00 PM.
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

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