This procedure is for 93-95 2.0 probes.

Remove the 4 bolts holding the iac valve onto the throttle body.
Turn the valve upside down and you'll see 3 cavities. (There are four cavity holes but only three actual cavities.)
What you want to do is; pour Seafoam (cleaner that removes carbon) into the cavity directly below the electrical solenoid.
Fill the cavity and completely cover the plunger (you can see the tip of the plunger inside of the cavity).
Look closely as you want to make absolutely certain that you pour the solution into the right cavity).
Leave the solution soak for 15 minutes.
Then, dump out the solution being careful not to get the fluid into the other cavities.
Apply compressed air for 20 seconds into both sides of the cavity to blow out the carbon deposits.
Again, fill the cavity with seafoam but this time do not let it soak. Dump the solution and re-apply compressed air and make sure all the carbon and seafoam are removed.
Connect the IAC valve to the engine harness making sure the key is off.
Hold the IAC valve and watch the plunger while an assistant turns the key to the 'on' position.
Do not crank the engine as coolant leakage will occur.
The plunger should move open and close quickly.
If the plunger does not move; the procedure must be repeated. (Remember to disconnect the IAC valve from the harness.)
If the plunger opened and closed normally; disconnect the IAC plug from the harness, then pour water into the solenoid cavity.
Dump the water out.
Do this 2 or 3 times.
Apply compressed air for 20 seconds until the cavity is dry.

1st thing check your coolant level..it must be topped off or the IAC wont get coolant flow thru it....the coolant temp affects the idle air bypass valve (thermostatically operated bi-metal valve) which is a part of the IAC...check that you dont have any vacuum leaks.. throw a vacuum guage on a vacuum line coming directly off the intake manifold..it should be 17-25 in hg at an idle speed of 750 rpms..check your base ignition timing..jumper ten to ground on 93ATX in the diagnostics box..93MTX ground the STI wire (single wire with a female connector on its end) which is next to a triangular female connector with like six terminals and four wires located by the strut mount..once the jumper is in place start the engine, set the idle to 750 then check and set the ignition timing at 10 or 12 BTDC (depending on if ATX or MTX) by loosening the 2 nuts holding down the disty and rotate till its at the right setting on the timing indicator on the lower timing cover..the IAC should measure like 10-12 ohms if i remember right + or - a couple ohms ..the TPS sensor could be misadjusted if the tamperproof torx screw has been removed..it should read 0.5 to 0.9 volts DC at idle on pins 2 and 3..pin one is reference voltage of 5 volts with respect to ground