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Thread: Bump/Miss/Hesitation in engine

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    Default Bump/Miss/Hesitation in engine

    Hi all,

    '91 Grand Marquis w/ stock AOD tranny and stock remanufactured Jasper 302 engine. Not sure how to exactly say what is going on regarding is it a miss, hesitation, etc but this started last week while driving 75MPH on the interstate on a trip from VA to NC w/ cruise control engaged and A/C off. The engine felt like it had a bump in it where you could feel it inside the car and it started several hours into the trip, so the engine was good and hot. Could have been a miss or hesitation too. I coasted to 65MPH and it went away. On the return trip back from NC to VA driving 65MPH no problems at all. Then this week at 45MPH while the engine is cold but warming up it does it again only I don't have the cruise control on. It went away the further I drove. This seems to occur randomly while lightly feathering the throttle to maintain speed or under slight acceleration to gain speed. No check engine lights are on. Any thoughts on what may be causing this?

    Matt

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    GMN Regular DerekTheGreat's Avatar
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    Check engine LIGHT. Sorry, that irritates me to no end

    How many miles? Does it burn oil? Could be it needs valve stem seals, these lopos tend to foul out the cylinders closest to the firewall. Ashley's old '89 fouled out the driver's side plug and produced the exact same symptoms you described.
    1985 LTD Crown Victoria - SOLD
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    12,000 miles on the remanufactured Jasper engine. It did use up some oil during the trip although I don't know why it would on a new engine? I had to add about half a quart when I got home.

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    I'm an air-conditioned gypsy gadget73's Avatar
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    Check the plugs and wires. Sounds like ignition misfire 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, 246k and counting

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    I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

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    GMN Regular knucklehead0202's Avatar
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    I'd definitely check the plugs/ignition like the others said. Also could be intermittent transmission slip, have had it present like this before.

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    Thanks. Will have to check the plugs and wires. The AOD does seem to slip on occasion when downshifting out of OD into 3rd while coasting not while accelerating. When it downshifts and you go to give it some gas the engine revs some before 3rd gear seems to engage fully. Have others experienced this at all?

    Matt

  7. #7
    I'm an air-conditioned gypsy gadget73's Avatar
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    only if the tv pressure is really low.

    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, 246k and counting

    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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    GMN Regular knucklehead0202's Avatar
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    Shall we assume you've checked/replaced your throttle valve bushing? If you're having AOD weirdness that's a definite place to check.

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    Yes, that bushing has been replaced in the past w/ the bronze one.

  10. #10
    I'm an air-conditioned gypsy gadget73's Avatar
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    could still have the pressure too low. If its shifting to overdrive under about 40 mph, its probably too low.

    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, 246k and counting

    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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    It upshifts fine, no problems there. Goes into OD right at 40 under normal conditions or if accelerating onto the interstate it will carry 3rd all the way to 55 before going into OD.

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    I'm an air-conditioned gypsy gadget73's Avatar
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    Sounds reasonable then. When its in overdrive at 30-35 you're likely to get weird slip/shudder crap.

    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, 246k and counting

    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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    When its in overdrive at 30-35 you're likely to get weird slip/shudder crap
    Could this also occur at higher speeds even up to 75?

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    Beater gonna beat sly's Avatar
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    technically yes, but the shudder issue is usually most pronounced between 35 and 45 mph. If the shudder is occurring at 75, then the shudder at 35-45 would be very noticeable. If it's the same-ish feeling up to 75, then it's probably fuel/spark related.

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    Yeah it's the same-ish feeling whether at 45 or 75.

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    Beater gonna beat sly's Avatar
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    Then engine related.

    Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
    rides: 88 MGM (SOLD), 93 Vic, 2000 Crown Vic, 2003 Expedition
    Quote Originally Posted by gadget73
    ... and it should all work like magic and unicorns and stuff.
    Quote Originally Posted by dmccaig
    Overhead, some poor bastards are flying in airplanes.

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    ok thanks.

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    I received my Motorcraft parts from Rock Auto today (AWSF44C plugs, wires, cap and rotor) and removed the aftermarket wires, cap, rotor and Motorcraft platinum plugs and installed the new parts. The platinum plugs were not gapped properly, they were all right at 46/47 which is under the 48-52 range specified. Plugs 4 and 8 were fouled the most with #8 being real bad. Plugs 1, 2, 3, 5, 6, 7 all look the same.

    Here are some pics of the plugs I removed. The first 2 pics are of the 6 "good" ones and the last 2 are the fouled ones #4 on the left and #8 on the right. https://www.snapfish.com/library/photos?website=snapfish_us&cobrand=snapfish&locale =en_US#state={"pgvw":"siav","aid":122805387904060}

    What do y'all think of the plugs?

    Matt

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    I'm an air-conditioned gypsy gadget73's Avatar
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    link doesn't link proper. wants me to log in or something. Try uploading them to here as an attachment.

    two rear plugs oil fouling is common on engines with wear. Not sure if it comes through the valve seals because of the tilt of the engine, or through the PCV system because of blowby but either way thats where you see it. Is the screen in place under the PCV valve? You'll get a lot of extra oil through there if the screen is missing.

    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, 246k and counting

    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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    Had to re-size the pics to get them to post.

    This is a new remanufactured engine. I'm assuming the PCV mesh screen is in place, it's nearly impossible to get back there to confirm w/o taking off the upper intake. What do you think of the pics? The first two are the "good" ones and the last two are plugs 4 and 8 with #8 being on the right and the worst of all of them.
    Last edited by MattDoscher; 04-28-2017 at 11:30 PM.

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