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Idle issue

Discussion in 'Ford Trucks' started by redskinsfan34, Feb 26, 2013.

  1. redskinsfan34

    redskinsfan34 Senior Member
    Messages: 966

    Every time my 97 F250 351ci sits for awhile (betwenn storms) it runs rough when first started then it idles high. Turn it off then start and it's fine. I had a more significant idle problem and was told to use the sea foam engine fogger which I did and it seemed to fix problem. This was a month ago. Now it seems the issue is back but much less severe (it's idling only slightly higher than normal now). Is it possible that the engine fogger didn't get all of the crap out that was causing the original issue and needs to be done again? Is it bad to fog an engine too often? Any suggestions appreciated.
  2. snowplowpro

    snowplowpro Senior Member
    from NJ
    Messages: 926

    When's the last time you gave it a tune up my 96 f250 does the same thing I need a tune up badly. Wires plugs cap and rotor. Your truck could be out of time which means your distributer cap and rotor are turning off time but could also mean your plugs or wires are no good.
  3. shovelracer

    shovelracer Senior Member
    Messages: 525

    There is no such thing as a fix in a bottle. Too much bottle could potentially clog cats or kill O2 sensors, this is a general statement not sure how much regulation the 96 had, but new enough to have some.

    As mentioned is possible, as is leakdown or moisture issues. Are there any issues with additional smoke upon initial startup? Fuel also tends to break down very fast these days because of the ethenol. That will gum up filters and injectors. Tune up might help, but if your really only starting it once a month if that you might want to change out your fuel filter as well.
  4. redskinsfan34

    redskinsfan34 Senior Member
    Messages: 966

    Thank you guys. It gets driven once every two weeks at the least. No additional smoke on startup. I think it could be moisture. After every storm I wash it and put it away and I've been told that's inviting trouble. The barn it sits in is unheated also. Oh I forgot. It got new plugs about a year ago because 2 were broken whilr replacing manifolds.
  5. shovelracer

    shovelracer Senior Member
    Messages: 525

    WD40 in the dist cap does wonders for moisture. Heard the saying drove hard & put away wet?
  6. linckeil

    linckeil PlowSite.com Addict
    from CT
    Messages: 1,272

    try the cheap, easy stuff first. these things should be part of routine maintainance anyway. get a can of throttle body cleaner, new rotor, new cap, fuel filter, air filter. check the timing (don't forget to remove the spout connector near the brake booster). as for the spark plugs, they are cheap, but not always easy.

    if the plugs are heavily corroded they will snap off in the head and turn into a nightmare. i pull my plugs every year and replace them as necesary to prevent them from becoming one with the cylinder head. always use never-seize on the threads. hold off on the plugs for now. squirt them with a 50/50 mix of ATF and acetone and let it sit for a few days. this is far from a gaurentee that your plugs will thread out, but its your only hope.

    but try the other stuff first and see how is goes.

    and FYI - the distributor likes to seize up in the block too, making it impossible to adjust the timing. if seized up, use the 50/50 acetone/atf mix here too.
  7. plowguy43

    plowguy43 PlowSite Fanatic
    Messages: 5,281

    I want to say my 5.0 did this in my bronco and it needed a new IAC. Which was then followed up by a TPS going bad.
  8. redskinsfan34

    redskinsfan34 Senior Member
    Messages: 966

    I think I'm gonna start with the dist. cap and see how it reacts thru this storm. It did the same thing for the last storm (last Friday) but once I drove it for a while it went away until I washed it, put it away, let it sit for 3 days, and then get it back out. I'm thinking moisture. Thank you for all of your replies!
  9. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,391

    Iac motor and maybe your egr sticking.
    Yes as mentioned ck your cap and rotor
  10. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    My 351 it was the throttle position sensor. They are a pain to replace. You have to take the section with the air plate in it, off. You will never get the Phillips screws loose from underneath. Replace the warmer / coolant lines when you do it. The idle air control works or not. I have never seen one increase an idle. Check your fuel pressure regulator too. If you take the vacuum line off when it's at a normal idle. The RPM will increase. Try it when the idle is high and see if it increases? Make sure you have vacuum to it when it high idles.
    Last edited: Feb 28, 2013