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  1. #1

    Default Capri 3.8L With Stock Engine Wonít Go Above 2000 rpm

    Hi, everyone Iím new to the forum. I have an 86 Mercury Capri with a stock 3.8L engine. Recently I was driving and the RPMs wonít go above 2000. So when Iím on the freeway it wonít want to go above 55mph. I try to accelerate but it just wonít want to go and the engine feels like it wants to choke. The car otherwise drives okay under 2k rpm. I also have recently done a lot of maintenance on it. Thank you in advance for the help.

  2. #2
    FEP Supporter Broncojunkie's Avatar
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    I would be looking at fuel pressure and cats (possibly clogged? ).
    79 Pace Car - 331, t5
    79 Cobra - working on 351w, t5
    82 Capri- working on 302, t5
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  3. #3

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    Quote Originally Posted by Broncojunkie View Post
    I would be looking at fuel pressure and cats (possibly clogged? ).
    The cats are new and the car runs well if itís under 2k rpm so the fuel pressure is good. Iím thinking something to do with the ignition but the coil, cap, rotor, spark plugs, wires, and TFI module are new.

  4. #4
    FEP Supporter Broncojunkie's Avatar
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    It's been my experience that rpm-related ignition problems usually show up as a misfire (breaking up, bucking, sputtering, etc.) Is it still running smoothly at 2k rpm, or does it feel like it's breaking up?

    If it's bucking, I would definitely look at ignition and timing first, but fuel delivery could cause that also.

    Just because it runs well at lower rpm doesn't mean it isn't a fuel issue. Your fuel requirements change with rpm and load.
    79 Pace Car - 331, t5
    79 Cobra - working on 351w, t5
    82 Capri- working on 302, t5
    82gt - working on 408w, c4

  5. #5
    FEP Supporter Broncojunkie's Avatar
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    Have you pulled a couple plugs to see what they look like? Might give you some insight.
    79 Pace Car - 331, t5
    79 Cobra - working on 351w, t5
    82 Capri- working on 302, t5
    82gt - working on 408w, c4

  6. #6
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    I concur with BroncoJunkie. Just because it runs fine at low RPM doesn't mean the fuel system is fine. You really need to check fuel pressure under load when it is breaking up. Possibly pump(s) and/or filter. That and cats were my first two guesses, but you said the cats were new.
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  7. #7
    FEP Super Member gr79's Avatar
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    A recent drop in mpg vs none may give another clue if needing retuning, repair, or both.
    May be related to recent maintenance. An overlooked detail like a vac line, loose spark plug wire.
    If new wires, recheck order on cap. Check for decent vac readings with a gauge.
    Last edited by gr79; 06-01-2021 at 02:52 PM.

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