where's the leak?

[That-Guy]

We have a 2000 ford explorer that has developed a problem. When it starts it idles really high over 1000 rpm's then slowly works its way down. If your driving and stop sometimes it will do a jump in rpm's. When you put it in park it will jump in rpm's. We tracked the problem down to the controls. If you turn the heat or AC on it will affect the idle. You can actually changed how it runs with the fan control. I'm almost certain it is a leak somewhere, but where? If it is a leak, we cant find it. It was never like this, it's the reason we got it for $1000 with 130,000 miles on it.

 

[That-Guy]

bump

 

[firepop5]

Could be a vacuum leak

 

[That-Guy]

thats what i figured, but where?

 

[kindred4x]

I have to agree sounds like a vacuum leak. They are a real pain in the ass to locate. check all your hoses, plus get a can of starting fluid and start spraying around your intake manifold area and throttle body and any hose those enters the upper intake manifold

 

[2000StreetRod]

vacuum actuated heating/AC controls

The heating/AC controls on my Sport enable/disable various vacuum operated items. If you cap the vacuum line from the engine to the heating/AC controller and your idle speed problems go away then you know to start looking at hoses and bellows behind the dash for splits.