fast idle constantly
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fast idle constantly
my 99 explorer limited 4.0 just started idling fast for no reason,it revs light it wants to idle down but it won't does anyone have a idea why it idles fast also my temp gauge is climbing to the high mark
New User
Joined: Jul 2003
Posts: 18
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Boss Man,
Just my 2 cents: Start by looking for a vacume leak. With truck running spray carb cleaner on/around lower intake and vacume lines. If truck sputters or reves even highter, that's where you have a leak. Or you can go over the running engine with an "UNLIT" propain torch to the same affect. 4.0 is famous for the lower intake bolts comeing loose. If thats the case just retorque them down. Another posibility is restricted air intake. Check the air cleaner. If it's dirty it my be restricking the air flow causing the mixture to run rich and iddle high.
You state the temp gauge goes to max. This may or may not be related. Do you have any coolant loss? Check you oil, does it look milky or chocolate brown? This would indicate coolant getting into the oil which could indicate a lower intake gasket leak, blown head gasket. Pull spark pulgs. A cristal like apperance on plug #5 is also an indicator of coolant getting where it was not intendid.
If nothing indicates coolant leak, take a look at your thermostat. It may be inop in the closed position.
Good luck and hope this gave you atleast a start point.
Just my 2 cents: Start by looking for a vacume leak. With truck running spray carb cleaner on/around lower intake and vacume lines. If truck sputters or reves even highter, that's where you have a leak. Or you can go over the running engine with an "UNLIT" propain torch to the same affect. 4.0 is famous for the lower intake bolts comeing loose. If thats the case just retorque them down. Another posibility is restricted air intake. Check the air cleaner. If it's dirty it my be restricking the air flow causing the mixture to run rich and iddle high.
You state the temp gauge goes to max. This may or may not be related. Do you have any coolant loss? Check you oil, does it look milky or chocolate brown? This would indicate coolant getting into the oil which could indicate a lower intake gasket leak, blown head gasket. Pull spark pulgs. A cristal like apperance on plug #5 is also an indicator of coolant getting where it was not intendid.
If nothing indicates coolant leak, take a look at your thermostat. It may be inop in the closed position.
Good luck and hope this gave you atleast a start point.
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