ADJUSTING RPMS/ / 4.2/ 131,000 MI

1998 Ford F-150

Tiny

hutch4

August, 22, 2006 AT 5:19 PM

I've just installed a tachometer in my 1998 F-150, it's a 4.2 l v6 five speed standard and I found that the rpms at idle are around 1500 rpm. How can I bring the rpms down and at what rpms should it be? Thank you very much. Hutch.

FOUND 3989 RELATED QUESTIONS

1 Answer

Tiny

Mikeybdman

August, 22, 2006 AT 5:41 PM

Should be 680-830 when warm. The idle speed is not adjustable.
Things that can cause high idle. Vacuum leaks, throttle plate and linkage, speed control linkage binding, intake air tube leaks, intake manifold, and itmes attached for leaks, such as EGR, and IAC.
If not leaks, I would suspect a bad IAC valve.

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