1. Vacuum leak- maybe?

    I have a 2003 Jeep Grand Cherokee Laredo (only 175K miles) that had developed a new problem that I've never seen. I am hoping it's as simple as a vacuum leak and not a transmission that's about to go south.

    It has an automatic transmission, but last week it was acting (in town driving) like I had my foot partially on the (imaginary) clutch. The car would move but acelleration was anemic to the max. When I got home, the first thing I did was to check the ATF level, and it was good. The next day I had to run an errand and it drove fine. In fact, it drove fine for the next few days. Then yesterday, on the freeway (70MPH), it would surge, for lack of a better word. The RPM's were steady but it was like I was tapping on the (imaginary) clutch. I slowed to 65 and the issue lessened a lot. Got to our destination, did our shopping then drove home. No more problems. Today, on the freeway again- no problems.

    So, experts. Transmission or vacuum leak?

  2. #2
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    Re: Vacuum leak- maybe?

    If fluid was full and color correct then clean the TPS and check the transmission output speed sensor.



    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

  3. #3

    Re: Vacuum leak- maybe?

    [QUOTE=JPNinPA;358401]If fluid was full and color correct then clean the TPS and check the transmission output speed sensor.

    Ok, what is the TPS and how do I find and check the output speed sensor?

  4. #4
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    Vacuum leak- maybe?

    TPS throttle position sensor. #6
    Vacuum leak- maybe?-image1635419308.526106.jpg
    Vacuum leak- maybe?-image1635421046.471879.jpg
    Tps is a voltage dividing resistor. Center pin resistance should vary as you open and close the Throttle Body.
    Sometimes dirt gets in. Fully Opening and closing the throttle body valve a number 20-30 of times can clear it. Some blow air in it. If replacing any sensor use OEM parts.


    Vacuum leak- maybe?-image1635419836.147165.jpg

    Never look down on anyone unless you are helping them up - Jesse Jackson
    Last edited by JPNinPA; 10-28-2021 at 07:39 AM.
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

  5. #5

    Re: Vacuum leak- maybe?

    Many thanks.
    So, you are ruling out a vacuum, leak?

  6. #6
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    Re: Vacuum leak- maybe?

    What rpm do you idle at?


    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

  7. #7
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    Vacuum leak- maybe?

    So what did you find?


    Never look down on anyone unless you are helping them up - Jesse Jackson
    Last edited by JPNinPA; 11-07-2021 at 08:19 PM.
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

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