1986 244, 150K+ miles, new to a friend who bought it & drove it home with info from PO "Idle just started going up over a few months; seemed like it would go up and come back but stayed a little higher each time we drove it."

The car started easily but idle went right to ~2500 and and hold. After it warmed up it would drop in one jump to ~2000 RPM and stay there.

Intake manifold gasket good; hoses good, no vacuum leaks (via listening and squirting water), no air leaks in the accordion intake. Pulled IAC and cleaned inside - resistance within spec. Cleaned throttle plate; cleaned electrical connections on IAC, ECT, TPS, MAF.

TPS clicked but throttle plate was open a bit. Throttle stop tab bent over. Straightened that; adjusted idle stop & TPS.

Put it back together and it started easily as before. Idled closer to 1000; when it warmed up a bit it dropped down 100-150 RPMs in one step.

I infer so far that the car had loose/dirty electrical & hose connections and the idle had been adjusted by someone unfamiliar with 240s.

I'll run some cleaners through the intake and drive it some.
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240 drivers / parts cars - JH, Ohio