My 88 300TE is being totally reconditioned to like new and there is one problem with the idle I need to correct. When the car is cold prior to putting it in gear to drive, it idles very fast until it’s warmed up some. It also surges to a high and low idle sometimes at a stop sign, after being driven for a bit and has gotten warmed up. If I kick the throttle to a high rev and immediately release it then it goes back to a normal idle. Is this due to some kind of idle control modulator that needs replacing?

Common on older models with KE injection. LOTS of potential causes, including air hose leaks, bad throttle switch, binding linkage, bad potentiometer in the airflow meter, OVP relay, footwell mat slipping over the gas pedal...]

Do a search on this site.

Steve

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'91 MB 190E 2.3
'08 RAV4 Ltd 3.5
'83 Lazy Daze m'home 5.7