1987 244 High Idle continuing problem

[Blue87]

Hello everybody. I have been having a continuing high idle problem with my 87 244. When I start the car for the first time everyday, it takes a second or so to start and then idles at 1000-1100 rpms. I can start driving around and come to a stop, pull off the clutch with the car in neutral and the car still idles high. The only way I have found of making the idle go back to normal temporarily is by engine braking while slowing down before a stop, and get this; by putting a drag on the electrical system by running the fan, turning the lights on and playing the radio. After I come to a stop after engine braking, the idle returns to normal below 1000 rpms for a few seconds and then returns to 1100. Turning the lights and fan on works at lowering the idle to 750 rpms.until you turn them off. I did replace the alternator a few months ago with an aftermarket but it idled fine after that.
Here is a list of the things I have replaced/cleaned attempting to fix the Issue: New intake hose(old one had a hole), cleaned and tested idle control valve, cleaned the maf sensor, and cleaned the flame trap.

Does anyone have any suggestions on what the problem could be? The high idle is driving me crazy.
Thank you for your time.

[93Regina]

what the problem could be?

Yes, too much intake air is causing the issue.

Make sure IAC is plugged in, and throttle stop switch is adjusted, and works.

Intake manifold might be sucking air...

Brake vacuum booster has a ruptured diaphragm...unplug hose and cap inlet port.

[mtd240]

what the problem could be?

Yes, too much intake air is causing the issue.

Or perhaps the car *thinks* it is getting too much intake air Any codes?

On mine ('90), replacing the MAF solved the high idle problem. Do you have a spare to swap in? They charge very little at the pick-n-pull for 'em.. I'm not generally a "parts cannon" kind of person, but past experience points to the MAF.

[93Regina]

Any codes?

Pre OBD-II codes may point, but one must confirm before buying.

With OBD-I vehicles, having a code reader was not required in many cases. Examining vehicle's mpg and tail-pipe is how I read a vehicle's health, unless other symptoms are obvious.

My experiences with MAFs failing is one experiences RPM variation-humping-at idle. Bosch has used a hot wire burn-off cycle, and sometimes this circuit fails, and sometimes it can be repaired.

[Blue87]

Thanks for the replies guys I will try to work on it today and see what happens.