Idle speed too high-won't come down
06-03-2005, 07:33 AM
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Idle speed too high-won't come down
I have an '88 5000 that recently failed smog and needed a tune-up. I did the usual (plugs, cap, rotor, oil, filters etc.) but still had a nagging issue pop up. At idle (only when hot) the engine idle would jump from 1000 to 1800 RPM and then fall back to 1000. Up and down continually. I went to a junk yard and replaced the idle stabilization valve to see if it would help. The up and down went away but I can't get the idle to drop below 1300 rpm. I've been looking for a vacume leak or something of that sort with no luck. With an idle speed that high, it is not likely to pass smog. Any thoughts anyone.
06-03-2005, 10:19 AM
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Re: There is a screw adjust above the throttle plate also
if the climate control is on anything other than econ it will boost the idle.
There's an ECU ground at the rear of the intake manifold that sometimes can cause strange idle problems.
The control module for the ISV is in the driver's side fuse panel.
There's an ECU ground at the rear of the intake manifold that sometimes can cause strange idle problems.
The control module for the ISV is in the driver's side fuse panel.
06-03-2005, 02:47 PM
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Re: Idle speed too high-won't come down
Missing idle screw, dirty or faulty ISV, bad ISV temp sensor, bad ISV control unit, bad ground, vacum leak...
Check all of the above.
Steve
Michigan
Check all of the above.
Steve
Michigan
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