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Thread: Frustrating Problem and Unknown Source

  1. #1
    Member fordnmerc's Avatar
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    Jul 2014
    Watkins Glen NY

    Default Frustrating Problem and Unknown Source

    This is with my '89 Crown Vic LX with 5.0 and 92k miles. I will give as many details as I can.

    When I got it in Sept of '19, it had a vacuum leak. I tracked that to the automatic parking brake release switch. Disconnected the hose and plugged it. Done.

    A different problem keeps persisting. On cold start-up, the idle would go back and forth between high and low for 20 to 30 seconds before smoothing out at low idle. Would be a bit rough sometimes after reaching low idle, though. At the same time, when shifting through the gears from Park, the engine rpms would go lower than normal low idle and occasionally cause a stall-out. Shifting between gears would also see a dimming of headlights and instrument panel lights. However, the alternator is quite new....I don't think that is part of the problem. After the inspection tech at the shop left my courtesy lights on and killed my battery (as detailed in a thread in the electrical forum) I got a new Die Hard Silver Series Group 65 battery.

    After installing the new battery, on cold starts the idle settles down to low very rapidly now....maybe in 15 seconds or so. There is no more up and down, back and forth, at the moment.

    But the problem(s) of loss of power when shifting between gears, and dimming of lights, still remain.

    Here is everything else that I can think of, in case anything might tie-in somehow:

    Slight coolant leak. Maybe 2 ounces every week or two. It sits in the little depression on top of the water pump. It leaks so slowly that you can't see where it's coming from while the engine is running. It *seems* to leak when sitting cold for several days, rather than when the engine is warm. It suggests to me contraction of an old hose or gasket as it reaches ambient air temperature.

    The exhaust system is rusting out. It's the only rust on the whole car, but it includes the catalytic converters. The cover shield for the driver's side cat dropped off onto the pavement last winter. There is rattling from the exhaust, at low idle, possibly from the cats. I have read that bad cats can cause various engine issues.

    The transmission was rebuilt in 2015. Shift points with the column shifter are a bit vague and come more between the letters than right on. At about 30mph, when traveling at slow speeds when there are stop signs every few blocks, when the transmission shifts from 1st to 2nd there is a 'chirp' and a harsher than normal shift....not bad, but you can feel a difference. Does that both in regular drive and overdrive.When road conditions are such that you can accelerate firmly and steadily, the transition from 1st to 2nd is normal and there is no chirp. Shifts to higher gears are normal. On the interstates, so far the car performs like new, with no issues at all.

    Last winter, there were a few times when starting out cold and reaching the first stop sign, the car would not move again after stopping until I put it back in Park and shifted again. Didn't stall, though. I attribute those instances simply to not actually having it fully in gear, because of the shifter vagueness, even though I thought I did.

    From all of the maintenance records that I received with the car, I found that the cap, rotor, plugs, and wires were all fairly recently replaced. The plugs that were installed are double platinum, according to the records.

    Anyhow, I have read all kinds of possibilities for this:

    Throttle body
    Bad cat(s)
    Issues with #4 and #8 plug wires
    Wiring harness
    Voltage regulator

    The list seems to be almost endless, as far as possible causes.

    I like this car and would prefer to keep it, but I can't afford to start replacing a lot of parts because *maybe* it is this or *maybe* it's that.

    Has anyone else had a Panther with this specific loss of power problem as I have described?

    Last edited by fordnmerc; 01-05-2021 at 04:08 AM.
    1989 LTD Crown Victoria LX
    14 previous Panthers, gone but not forgotten....

  2. #2
    The Brown Blob 87gtVIC's Avatar
    Join Date
    Sep 2008
    Whitestone, NY


    You can try and unbolt the IAC (on back of throttle body) and clean it out really well. Clean out the throttle body as much as you can as well.

    This may be attributing to your idle dips between gears while in park. When foot on brake and you shifting into gear there is more load on the engine. The load caused your lights to dim etc and a weak IAC may not be able to quickly compensate for the change in air needed.

    You state alternator is new. Is it a stock replacement 65amp? That can be part of the problem. They were not great since their inception and coupled with a weaker battery (which you stated you had..deduced because you have now installed a new one and problem is better)) may have exasperated those voltage drops between gears. A 3g alternator swap is a recommend upgrade from the fire prone weak factory 65amp alternator.

    The shift indicator is adjustable, this is merely an indicator for visual reference and does not affect what gear the tranny is in directly. Removing the steering column covers will reveal a white plastic collar around the shift tube. It has a small fastener that when loosened becomes your adjustment for what you see up on the dashboard. These often break.

    Have you check your transmission fluid level when car is at full operating temp while vehicle is on? Have you checked underneath the throttle body to ensure your throttle valve cable (cable that is connected between throttle body and transmission) is secure and the bushing is present and nice and tight? I would highly highly highly advise to no longer drive the vehicle if you find that there is no TV bushing on the throttle body. I would also advise to not drive the car if you find it is really low on fluid.

    You description of taking a long time to engage into gear sound like low fluid to me and not so much as you just putting it into the wrong gear as you can easily feel the detents between park, reverse, neutral, OD D and 1. Again, those detents are direct connectins to the trans and the indicator can be adjusted via the adjuster under the steering column cover to match them as best as possible.
    Last edited by 87gtVIC; 01-05-2021 at 07:08 AM.

    My 1987 Crown Victoria Coupe: The Brown Blob
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  3. #3
    Wagon Addicted Tiggie's Avatar
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    Mar 2006
    Bedford, VA


    I agree with David on all these points. Cleaning IAC and throttle body, and checking the TV bushing would be my first stop. And the trans fluid.

    Your TV adjustment could be a little high. What’s chirping? The tires or the transmission? Some AOD’s make a chirp like noise going from 1-2. It’s the same noise you hear from the first gear whine (100% normal), just coming to a peak and an abrupt end as it gets into second. You can check the TV adjustment ballpark by checking that the throttle can go wide open at the same time as maximum TV cable movement (the car off). If it’s the tires chirping, someone installed a shift kit.

    My 88 had the same coolant leak. I drove it for 13 years like that. It never got worse. In my case, it was right side head gasket. It could also be the intake gasket. If it’s not dripping, I wouldn’t worry about it.
    1990 Country Squire - weekend cruiser, next project
    1988 Crown Vic LTD Wagon - waiting in the wings

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  4. #4
    GooGooG'Joob Quincy's Avatar
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    Dec 2020
    Southeast USA


    Quote Originally Posted by Tiggie View Post
    I agree with David on all these points. Cleaning IAC and throttle body, and checking the TV bushing would be my first stop. And the trans fluid.
    Thirded. IAC would be my first stop. Also, you'd be surprised what simply cleaning any possible crud off of the throttle valve and surrounding airflow surfaces onside the throttle body can accomplish. Just a little restriction in this area at idle can throw the whole works outta whack!

  5. #5
    I'm an air-conditioned gypsy gadget73's Avatar
    Join Date
    Jan 2005


    What they said. Might be worth inspecting the connector at the alternator but the stock 65a just does not have wonderful low speed output. Pretty normal for those to dim the lights somewhat when coming to a stop. Its worse with the fan on, you can actually hear the blinkers and fan slow down as you come to a stop.

    and +1 on the IAC and checking vac lines. Leaks and sticky idle control both make the idle roll annoyingly.

    check the clamps on the hose between the WP and t-stat housing, and the upper rad hose.

    Does the shifter click solidly or does the handle just flop around? When mine had a broken spring on the shift handle and a broken indicator it was a bit difficult to get in gear reliably. Once I fixed the detent spring it was easy to just count the clicks and ignore the indicator. That plastic collar for the pointer breaks fairly often on these, so having it be "somewhere" is pretty common.

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

  6. #6
    Member fordnmerc's Avatar
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    Jul 2014
    Watkins Glen NY


    Many Thanks, guys.

    It's great to have agreement on the most likely culprits. While nothing is guaranteed, I feel quite confident now that this can be resolved without chasing a lot of false leads and spending big $$$. That's very important these days.

    Chirping is definitely the tranny and not the tires....glad it's normal, though.

    Shifter is not sloppy, but yet considerably vague.

    I have a friend from my high school days who is a mechanic and we will get into these issues soon.

    In the meantime, it's only being driven 3 miles round-trip to Walmart for groceries every 2 weeks in this pandemic....and started up each week in between.

    I will update this thread to pass along the progress when I can.

    1989 LTD Crown Victoria LX
    14 previous Panthers, gone but not forgotten....

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