Cold Start..High Idling

[mike_versluys]

Dear Friends, I´ve problem on a 97 explorer 4.0
When start up engine in the morning, engine idles at 2.500 -3.000 rpm very rough.
After 2 or 3 minutes she comes down to 900 rpm and then will run ok.
At the w-shop they plugged in to computer, and they can not find anything wrong. Then after a couple of minutes when engine starts to warm up and idling gets back to normal. Then they have to wait to the next day to try again......... The car has been in the work for 20 days!
Anyone knows what to do about this thing !!!!
Looking forward to your reply,
Regards from Spain.

Mike Versluys

 

[TPLYNCH]

Does it have the SOHC or the OHV 4.0?

 

[mike_versluys]

The engine does not have overhead camshafts

 

[MazdaGreg]

Hmmm.. If it runs that way for 2-3 minutes, it really sounds like the engine is getting a whole lot of unmetered air from somewhere. I'm sure the shop is onto this problem, and trying to figure out from where it is. The engine with the IAC can eventually compensate, but it is tough when the idle's that high. When i initially start mine, it revs to 2200 or so, and rests about 1300, until warm. That's definately too high. wish i had answers, but i think your shop should be able to find something.

 

[mike_versluys]

Explained myself wrong

When I mentioned that the engine goes up to 3000 RPM, that means that goes up and down from 500 upto 3000 and so on. Sometimes when you put her in DRIVE (auto-tranny) she can even stall. And then after 2 minutes, she go fine and smooth.

Any sugestions ??
Thanks in advance !!
Mike

 

[mike_versluys]

Join Date: Apr 2004
Posts: 8 Explained myself wrong

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When I mentioned that the engine goes up to 3000 RPM, that means that goes up and down from 500 upto 3000 and so on. Sometimes when you put her in DRIVE (auto-tranny) she can even stall. And then after 2 minutes, she go fine and smooth.

Any sugestions ??
Thanks in advance !!
Mike

 

[TPLYNCH]

Those symptoms are very much the same as those with SOHC engine with the Intake Manifold O-Ring problems. If you are sure you don't have the SOHC, then check and make sure the intake manifold bolts on your OHV engine are tight and there are no leaks around the gasket. Just for the heck of it, you may want to clean you IAC and MAF sensor. see here - http://www.explorerforum.com/forums/showthread.php?threadid=56770&perpage=25&pagenumber=1

 

[monkeydude3]

check and probably replace your throttle position sensor and idle air control valve... my friend's 1991 explorer (SAME ENGINE!) had the same exact problem and those were replaced and fixed it... TAKE CARE!!

TPS AND IAC!!!!!

George