I have a 2001 ford 4.0L SOHC in a sporttrak runs great all year except when its about 40F outside idle acts like it wants to stall. I can baby it and get it running again after it stalls like this but it must be some cold air thing for it to act this way only in cold months. Any ideas are welcome.
You most likely are experiencing leakage past your upper plenum orings, and to a lesser extent, lower intake manifold oring gaskets. Your problem may still be in the early stages of failurre where no trouble codes have set, but you still get an occasional cold stall or idle fluctuation.
Cleaning or replacing the IAC is cheap enough to do -- they do fail quite often -- but you need to get ahold of a Ford dealer and see if your VIN and mileage allow you to qualify for the intake gasket replacement recall. I don't know what the recall's mileage cap is, but a 2001 4.0 V6 should qualify for the repair.
Toyota MDT in MO
thx. I may try the IAC myself before going to the trouble of taking it to a dealer. aka scheduling the appt, alternate transportation for the day etc.
Correct. I just assumed that the OP would not benefit from my going into detail, but yes, look for cold temp total fuel trim numbers that are high positive but below the threshold of setting a P0171/P0174, ie ~15% to 30%. The intake problem more likely is the issue as colder temps don't affect IAC operation nearly as much. (they're just junk parts to begin with :) )
Toyota MDT in MO
Hard to see in the pic, but can anyone tell me if that valve is supposed to be 100% closed when its at rest? Mine sure isnt. Even after cleaning it, its not.
The local parts place doesnt have one in stock I can look at but I will sure change it if I need to.
No. It is slightly open all the time when the engine is off. The solenoid opens it to increase idle speed or the act as a dash pot. When the engine is dead, there is no vacuum to close it the rest of the way and gives the engine a bit more air during starting. This helps with those multitudes of throttle bodies that are sludged shut. As soon as the engine starts, the ECM takes over along with the force of engine vacuum. If you are cleaning it, use a small screwdriver to make sure the valve moves easily a short distance. Do not force it.
Lugnut
thanks for the info everyone. good forum.
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