Quote:
Originally Posted by petervankleeck
After reading the tach from the HVAC display, while the tach reads 4K the actual RPMs are 1750. Still very high but less than twice the reading. Anyone know how this disparagement occurs between the tach and engine?
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First I would check throttle position sensor voltage. This should read around 5.4 volts (if I remember correct).
Also, get a spray can of throttle body cleaner, remove idle air control (on the passenger side held in with two torx head bolts), clean the IAC motor pintle and use cotton swab and spray cleaner and clean out passages where the IAC slide in.
I seem to recall something about unstable idle on 1990 model resulting in revised PROM calibration. Someone more familiar with 1990 chime in please! Marc would certainly know and his revised PROM would have addressed this if the issue exists.
Like I said Peter, call me at 703 980 8814. I am not that far away from you.