Question about 1998 Ford Crown Victoria

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1988 Ford Crown Vic Strange Idle

I have a 1988 Ford Crown Vic with the 5.0L EFI.

Upon start-up the engine has a alternating idle between high and low RPMs....Then if i put it into gear, the idle becomes EXTREMELY rough, and tries to shut the car down.

After i give it a little gas, and drive down the road, it stops, and run absolutely fine..

PLEASE help me, i just bought the car...

Ive ran injector, and fuel system cleaner through it, as well as changing the fuel filter.


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  • 7 more comments 
  • Bill Jun 23, 2009

    I will take it to Autozone tomorrow for sure, i was thinking that it may be the idle sensor today, but was unsure because of the check engine light not lighting.

    If nothing comes up on the Diagnostic screen, where do i go from there?


  • Bill Jun 23, 2009

    Also, could it still be a sensor even though it stops after a little bit of driving, then doesnt start up again until i shut down, and restart?

  • Bill Jun 23, 2009

    Ok thanks, i know for a fact its not the filter, i just put a new one on today.

    If the idle sensor is not reading right in the ECU, what would that mean?

    Is there any way to "reset" the ECU?

    thought i heard you could disconnect batter for like 5 minutes?

  • Bill Jun 23, 2009

    Any recommendations on what to use to clean it?

  • Bill Jun 23, 2009

    ok great!

    i have another question, and i hate to do another post, maybe you know..

    my horn is sticking, and i had to pull the fuse...

    is it the relay? or could it be the switch in the wheel?

  • Bill Jun 23, 2009


    those switches...

    are they a pain to replace?

    im only 16, and i do most of the work myself, but problems are just piling up on this thing....


  • Bill Jun 23, 2009

    Figured so...

    well there's a good side to this,

    always looked for a reason to buy one of those racing wheels with the horn switch in it from Advance Auto, lmao.

    now i have a real good reason, cause right now, i wont pass inspection.

    Thanks for all your help!

    ill have to pull the O2 sensor tomorrow and clean it after i take it over to Autozone.

    You have yourself a wonderful 4th of July!

  • Bill Jun 23, 2009


    but no,

    the 88 doesnt have airbags i dont believe....


    i dont think so?

  • Bill Jun 26, 2009


    The Check Engine light is not burn out, or light up...

    i took it to Autozone anyway.

    got nothing.

    Its getting worse, and is not starting to stall under light acceleration. When sitting at a red light, it idles so rough it rattles the entire car.

    Now i am starting to hear a rattling coming from the bottom end.

    I have replaced the plugs, wires, fuel filter, changed the oil......i have NO idea what's going on...

    any ideas?



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  • 439 Answers

When you turn the key on does the check engine light come on? If not it may be burned out. It sounds like a MAP sensor or an O2 sensor is bad. I would suggest taking it to autozone as they do free diagnostic and seeing if a code comes up. If it is a sensor it should, if not it may be the idle sensor not reading right in the ECU. More than likely it is one of the sensors though.

Posted on Jun 23, 2009

  • 4 more comments 
  • Matthew Boulden Jun 23, 2009

    If nothing comes up, I would pull the MAP sensor or at least check the connection. I would also pull the O2 sensor and clean it. If this does not work you may have a partially clogged fuel filter or a weak fuel pump. Beyond that I would say injector, but that is highly unlikely.

  • Matthew Boulden Jun 23, 2009

    The only way to reset the ECU is to remove all power from it,(disconnect the battery) for 10-15 minutes. When you hook the battery back up it will go through a reboot. And yes, I think it could be a sensor because when you drive it blows extra air across the sensors cleaning them enough, or the ECU compensates for the issue. You see the O2 sensor gets alot of carbon build up on it that needs cleaned. I hope this helps you a bit more.

  • Matthew Boulden Jun 23, 2009

    I wire brush and brake cleaner as it evaporates at a fast rate or alcohol. But the wire brush should do the trick rather nicely.

  • Matthew Boulden Jun 23, 2009

    On these, normally it is the switch in the wheel, but the relay is the easier of the two to test as there are multiple relays that are the same under the hood you can test it with. Just pull the relay for the horn and another relay, and put the other relay in the horns place and see if your problem persists. If so it is the switch on the wheel.

  • Matthew Boulden Jun 23, 2009

    It depends on where the switch is on your wheel. Well, no it does not. They are both a pain in the Glutes. Most people actually splice the switch wires to a push button you can buy at autozone that is cheaper and easier than pulling the factory switch.

  • Matthew Boulden Jun 23, 2009

    You too, sounds like a plan, just take it easy with the airbag switch, you do not want to short one of these out.



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