'99 explorer running rough when cold
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'99 explorer running rough when cold
My parents explorer wont run right when its cold. It threw a check engine light and they got that checked to find out that the reading was the left bank running lean. My father has tryed changing the MAFT but that didnt work so were kind of stuck. The strange thing is that if you unplug the MAFT the engine runs fine. If you unplug the ECT it will run fine but if everything is hooked up the way it should be it wont run when cold. Has anyone had this problem before? If so what is the fix? Oh and its a 4.0 V6.
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Originally Posted by supersonicss
My parents explorer wont run right when its cold. It threw a check engine light and they got that checked to find out that the reading was the left bank running lean. My father has tryed changing the MAFT but that didnt work so were kind of stuck. The strange thing is that if you unplug the MAFT the engine runs fine. If you unplug the ECT it will run fine but if everything is hooked up the way it should be it wont run when cold. Has anyone had this problem before? If so what is the fix? Oh and its a 4.0 V6.
I am having the exact same problem with my 94xlt I am suspicious that it is the beginnings of an intake manifold gasket failure. I have posted with all my symptoms here for a 2nd opinion https://www.ford-trucks.com/forums/s...d.php?t=337968
Respectfully
Dean
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I would suspect the intake manifold O rings and a faulty IAC valve are at fault. I had both problems and the exact symptoms you describe, except that I never messed with any of the sensors or computers. Look at the sticky on the top of this forum and test the IAC valve. Odds are...its bad. Losing an IAC is not uncommon on these engines (4.0 SOHC). The O rings are also notorious for leaking. If you're doing the work yourself, go ahead and replace both sides to alleviate any future problems. Good luck!
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Well last night we pulled off the upper intake and checked that seal. We were going to replace it but no one has it in stock. Today we put everything back together and it was still running like crap. I disconnected the MAFT and it ran fine. I really dont think its a seal if this happens. Has anyone ever had trouble with the MAFT wiring harness? Or even the computer perameters? We have also ohmed out the IAC and it shows it works fine. This is also on a SOHC engine not a OHV.
Last edited by supersonicss; Jan 30, 2005 at 12:08 PM.
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