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Thread: 86 CP Misfire

  1. #1

    Default 86 CP Misfire

    Please help! I took my 86 out for a ride and after it got warmed up it started missing like crazy but only when accelerating. Idles perfectly smooth. Any ideas what can be going on here? I am new to these cars and used to carburetors lol

    Any help will be so appreciated

    Thank you
    Sal

  2. #2
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    How old are the coil and ICM?


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  3. #3

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    I really don’t know, the coil looks original. Not sure about the ICM. I’ve only had the car about 4 months.
    Are those known problems with these?

  4. #4
    I'm an air-conditioned gypsy gadget73's Avatar
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    age of the plugs, wires, cap, rotor, and condition of the terminal on the coil would be what I want to know. Under the EFI system its an engine designed in the 1950s and needs the same kind of maintenance.

    The ignition modules go bad but I wouldn't jump to replacing it before knowing the basics are in good operating condition. High load, low rpm misfire very much sounds ignition related to me.

    86 Lincoln Town Car (Galactica).
    5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

    91 Lincoln Mark VII LSC SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks, Holley SystemMax1 lower intake, SilverFox AOD valve body,

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  5. #5

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    Thank you so much! Gives me a place to start. Does the fact that the misfire is worse when the car is hot give you any clue as to where to start?

  6. #6
    Beater gonna beat sly's Avatar
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    If there's over 80K miles and the timing chain is original, it could be the plastic cam gear going away and allowing a lot of slack.

    If it is solely temperature related, it could be the computer temperature sensor near the thermostat housing (2 wire) or the ICM starting to go bad.

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  7. #7
    GMN Regular DerekTheGreat's Avatar
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    What gadget said. The ignition system is taxed the hardest while under part throttle load. I deal with that every now and again with my GM TBI stuff. Often ends up being the contacts at a plug or at the cap. This time for me, it was cylinder #3- the boot had gotten a tear in it somehow. Last year it was one of the terminal ends not making good contact at the cap on cylinder 4 or 6. In both cases, it ran fine under all conditions except part throttle acceleration.
    1985 LTD Crown Victoria - SOLD
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  8. #8

    Default

    Well so far I’ve changed.....
    Plugs
    Cap
    Rotor
    Wires
    Coil
    ICM
    Fuel filter
    Cleaned injectors
    Tested injectors
    Checked compression

    And no change

    Any other suggestions?? Please!

  9. #9
    Wagon Addicted Tiggie's Avatar
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    I think I would pull codes before throwing more parts at it.

    My thoughts include throttle position sensor, EGR issues, oxygen sensors.
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  10. #10
    I'm an air-conditioned gypsy gadget73's Avatar
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    if the codes get you nowhere, about the only other thing is the pickup in the distributor

    Whats your plug wire routing look like? 7 and 8 cannot lay next to one another or it can cause some problems too. If you still have the wire routing clips on the valve covers, put them on opposite ends of the clips.

    86 Lincoln Town Car (Galactica).
    5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

    91 Lincoln Mark VII LSC SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks, Holley SystemMax1 lower intake, SilverFox AOD valve body,

    1984 Lincoln Continental TurboDiesel - rolls coal

    Quote Originally Posted by phayzer5 View Post
    I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

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