Ford Repair: Idle speed to high, mass air flow meter, air intake hose

Question
How do you adjust the idle speed on a 2.3L four cylinder. 1991 ford ranger.  It idles to high even when warm. I have taken off and cleaned the ISC valve, but It did not do any good. There is no check engine light on.

Thanks for you help

Answer
Hello and thanks for your question.......I'll try to help.
Even though there is no check engine light on, check it for codes....this is always a good starting place. If it has codes, correct them FIRST.
Next, the idle usually isn't a problem with these engines.
I would like to suggest that you check a few things first before try to adjust the idle.
Verify the ignition timing.
Check for Vac. leaks........hoses, air plugs, air intake hose after the mass air flow meter (if it has one)

Now let's check the idle. Start the engine and get it up to operating temp. Keep it in Neutral for standard transmission, with E-brake applied. Park, for automatic, with Ebrake applied.
Now remove the electrical connector from the IAC motor.
Does the idle change? It should drop, almost to a stumble/rough running condition........it might even stall.
With the motor still unplugged, there should be a set screw on the throttle body that will allow you to adjust the idle.
I believe that it should be around 700 to 800 rpm, while in drive......set it to this and, then shut the car off before reconnecting the IAC motor. Disconnect the battery, to clear any codes that might of been set. And try it out.
I hope this helps,
Erik