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Thread: High idle after hard accel.

  1. #1

    Default High idle after hard accel.

    Just purchased 1966 Ford Fairlane with a mid-80s Mustang 302 engine with a carburetor, Ford part number D4JL-9510-J part number. Holley list: 7128, date code: 1658.

    When car is 1st started, idle is set at ~700 RPM. I'll take it for a drive & floor it. The car will not return to idle. Engine will running 2000-3000 RPM. Idles at ~45 MPH. I check the idle set screw and it's still sitting against the idle plate as before. What's causing this issue and how do I fix it? If you turn the car off and start it later, it's fine. Seems as long as you don't floor it, there's no issue. Please help.

  2. #2
    Join Date
    Nov 2014
    Ont. Canada


    The primary may be closed, but is the secondary closed?

  3. #3


    Look to see if there are any signs of the linkage hitting your manifold. You might be getting something hung up at full throttle. What happens if you kill it and then start it right away? Is the 2000 RPM in park or in gear?
    Last edited by evilokc; 05-31-2018 at 06:55 PM.

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