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Rough Cold Starts

Discussion in 'Ford Trucks' started by velocity, Dec 7, 2002.

  1. velocity

    velocity Junior Member
    Messages: 4

    Hello...I have a 1998 Ford Explorer with a 4.0
    SOHC Motor. When I start it on cold mornings it will not idle right. I have to keep my foot on the gas to keep it running. When the car warms up it is fine. I replaced the Throttle Positioning sensor and that did not help. If anyone knows what is wrong could you please help me. Thank you very much.
  2. Mike 97 SS

    Mike 97 SS Banned
    from U.S.A.
    Messages: 1,106

    Is the Check Engine Light on? I would guess that the Idle Air Control solenoid isnt working properly. Its definitely gonna be one of the sensors acting up. You know though there is another sensor that makes the motor run slightly faster when cold, sort of like a choke on old carbureted cars, i think its called the Coolant sensor if im not mistaken. I think it judges how much fuel to give the motor by reading how hot the coolant is and that gives u a slightly faster idle at start up. Anyone else here that might be able to jump in? Mike
  3. velocity

    velocity Junior Member
    Messages: 4

    Yes the check engine light came on. I cleared it out by disconnecting the battery. The problem still exists but the light has not come on again.I did have it on a machine and no error codes came up. I thought it might be one of the air sensors. There is a engine coolant sensor, intake air sensor and I believe the mass airflow sensor. This could get costly if i choose poorly. Thanks for the help.

    CARDOCTOR PlowSite.com Addict
    Messages: 1,312

    Probaly bad idle air control selonoid you can remove and clean
    it but your better off just replacing it. ford is having alot of problems with this part. in my shop we ve already replaced
    about 15 iac motors for the same problem .


    GO EAGLES!!!!!!!!!!!!!!

    SIPLOWGUY Senior Member
    Messages: 686

    We got Econolines at work. On the 2001's they had a run of bad IACs.
  6. velocity

    velocity Junior Member
    Messages: 4

    Well I appreciate the help..But the IAC did not work. It still will not idle until it is warm. I don't know what to do. I would hate to take it to the dealership. Anymore ideas would be helpful.