i have an 87 5.0 just put some mods on it and the car runs great when i stick my foot in it but it surging idle like crazy if i idle it BELOW 1200 RPM and shuts off and still sometimes at 1200.Iv looked all over the internet at these IAC Restrictor Plates and read nothing but good things about them fixing idel problems,what do you guys think...And yes iv read the surge idle check list.
Put one on my car to cure surging idle (nothing else worked) The plate helped out more than anything else I tried, but did not fix the the problem 1oo%. Good Luck
i use one. heres what you do. you getsome thin sheet metal and trace an outline with a iac gasket. then cut it out with sheet metal scissors. then just slap it on there of cours. youl need another iac gasket too because you need one on both sides of the plate
They are worthless. If your car surges there is real problem. This fix is a bandaid. Instead of blowing money on one of these, spend the money to find out what is actually wrong. If you are not mass air yet, you car may be telling you it's time.
One other thing that you can try is a PCV valve from a 351 W P.U. If you have put a cam in the engine the loss of manifold vacuum at idle can cause the PCV to not operate as it should. A PCV from a larger displacement engine has a different spring rate to it and can cure some, but not all idle surge problems. I have used a PCV from a 7.5 L truck to get the result I needed. Just a thought.
i had the same problem with my car, so i got a piece of aluminum and made a restrictor plate. it helped the situation but did not completly cure it. 2000xp8 is right it is just a bandaid for the problem. i just replaced the iac valve for a different reason and set the tps correctly and now the car seems to be running good idiling at about 750-800. when i put the new iac valve on i took the restrictor plate off.
If you are still speed density, the heads and cam have altered the vaccum characteristics enough that the computer may not be able to compensate for the changes. If you are Mass Air, you may have read the "Surging Idle Checklist, but how much diagnostic work have you done? What did you get for codes? Will the engine idle at 650-725 RPM without the IAC connected? Where is your ignition timing set?
For starters 86,87 and 88 cars are not mass air originally. 88 cars from california only are (not sure if it's all of them, but i know it's some). 89+ went to mass air. The mass air meter is a silver thing, about the size of a big beer mug right before the air filter/box. It has a sensor on top. Someone will have a pic, my car has a power pipe that puts in the fender, so there is nothing to see in my pics.
