IAC restrictor plate installed!

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When you guys get these and install them, the procedure below will finalize your idle.

'94-'95

Begin with a cold vehicle. The idea here is to get the car to a firm cold idle with enough air bleed capacity left in the idle circuit for IAC adjustment.

The idle stop should be set first. Back out the idle stop screw, away from the bell crank arm, until about 1/2 turn past the point where it no longer makes contact (blade fully closed). Using a 0.010" feeler gauge, tighten until gauge just drags between screw and bell crank arm. Remove feeler gauge. Tighten screw exactly 1 1/2 turns. If the screw is very loose, put a drop of loc-tite or silicone on it, so it doesn't work out of adjustment.

Now remove the connector to the Idle Air Controller (IAC) just on the other side of the throttle body. Start the car and allow vehicle to warm for 2 minutes. Give a small "blip" to let it settle. If it is having a hard time staying running you may have to get an assistant until you can get to the front of the car. Now open or close the air bleed screw (CCW opens) next to the IAC until the car idles at 575 to 600 rpm. For guys with aftermarket cams and an EEC tuner, you might want to idle a bit more briskly, say 650 to 675.

Obviously, this rpm range is by what the car and driver wants...IE, no set idle speed, whatever works for YOU.

Turn off the car. Now count the number of turns clockwise to close on the idle air bleed screw. If it falls between 1/2 and 2, it's okay, now reverse it out the same number of turns. Log the number somewhere in case you need it for the future. Reconnect the IAC. You are done.

If the air bleed screw is above 2 turns, it's a good idea to tighten the idle stop screw another 1/2 turn, and then repeat the idle setting. If it is below 1/2 turn, then loosen the idle stop screw by 1/4 to 1/2 a turn, and repeat the idle setting. Be sure to put another drop of silicone RTV on the stop screw if it was disturbed. Reconnect the IAC. You are done.

Another variation for the 94-95 cars is to reset the idle in the procedure listed above and get the car to idle as low as possible with idle control OFF and the IAC unplugged. (Around 600-650 rpms). Then plug the IAC back in, turn off the engine and unhook the negative battery post for 20 minutes. Then hook everything back up and put the desired settings in the PMS for idle control ON. Start with the percentage around 40% in the PMS air bypass setting and work from there. Once you set the desired idle RPM in the PMS, save and start the car. After a minute or two it should be able to control the idle.
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I have been dealing with this problem but I finally figured out what was wrong. It voltage at the tps was too low. Mine was idleing around 1100 to 1500 rpm as well. Once I got the voltage to .98 I reset the computer and its been idling fine right at 750 rpm solid. I don't knock the plate especially if it works just thought I would throw in my .02
 
Your 100% correct, that is why in post #127 I gave the idle adjust procedure. Part of that is to get your TPS voltage within range. I have a friend that did a TFS HCI and could not get the car to idle. With his new T-body the TPS was at .61!! When he set it to .98 it ran fine.
 
Has everybody received their plates? Is everybody enjoying them?

Alright... Just installed mine... I have yet to street test it... but I have a great idle at 750. Since my h/c/i install in '99, I have had to keep my idle around 900 to keep it from stalling. Just in my garage I already notice a difference. I will keep you posted as soon as I street test it. You are a tribute to mustangers, thanks! :flag: :SNSign: