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What causes the idle speed to run erratically between normal and 2500 RPM all the time?

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Wiki User
2008-09-08 13:33:08

Look for a vacuum leak. It may be on the throttle body or it may

be associated with the EGR valve assembly. Sometimes you can spray

a small amount of starting fluid at a suspected vacuum leak and if

there is a leak at that point, the engine will suddenly start to

sound different while it burns off the starting fluid. For a

vehicle to have a pulsating idle from approx. 800 rpm to 3000 rpm

approx. the issue is not with vacuum but with the TPS ( throttle

positioning sensor).

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