Idling problem
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New User
Joined: Jan 2011
Posts: 17
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Idling problem
I have a 91 f150 351 and auto trans
It almost always idles at 2000 rpms after i start the truck and after im driving around for a while it will sometimes drop down to the normal idle range.
If i unplug the air bypass valve it drops to around 500 rpms but i dont really like driving around like that because it likes to stall that way
What could be wrong and is this a common problem?
Thanks
It almost always idles at 2000 rpms after i start the truck and after im driving around for a while it will sometimes drop down to the normal idle range.
If i unplug the air bypass valve it drops to around 500 rpms but i dont really like driving around like that because it likes to stall that way
What could be wrong and is this a common problem?
Thanks
Cargo Master
Joined: Jul 2009
Posts: 2,541
Likes: 54
From: Des Moines
Well it could be a bad IAC valve.
It could also be a vacuum leak. That's where I'd start looking. Carefully check the condition of all the rubber and plastic vac lines. Remember that the plastic lines can crack and break easily, and sometimes it's not easy to spot the breaks in them. Also keep in mind that, when it comes to rubber vac lines, they can be sealed when they're cold and then when they heat up, they expand and the cracks start leaking.
It could also be a vacuum leak. That's where I'd start looking. Carefully check the condition of all the rubber and plastic vac lines. Remember that the plastic lines can crack and break easily, and sometimes it's not easy to spot the breaks in them. Also keep in mind that, when it comes to rubber vac lines, they can be sealed when they're cold and then when they heat up, they expand and the cracks start leaking.
Post Fiend
Joined: Jan 2005
Posts: 8,402
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