Idling issues and in need of some help!

tinnocker

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What does yours idle with the b-cam. I have been dealing with everything you are talking about on my 94 GT with aluminum heads, comp cam, and gt40 ported upper and lower manifold. I have set the idle by several different means from the forums and can not get it any lower than 950-1000 rpms. I can get a good idle but when I plug the idle control back up the computer kicks it up. The 94-95 has a different computer than the Fox body Mustangs and has what is called a dashpot. It is designed to have a short hanging rpm between shifts and to hold the rpms at 1200 or so when coming to a complete stop. I have read where some tuners can go in with a soldering iron and fix the problem we are having. My last attempt was to use the "band-aid" fix. I used the IAC gasket as a templet and fabbed one out of thin aluminum but instead of the two large holes I made one of them about 9/32''. It helped as much as anything I did. It starts good, still idles at 1000 rpm but doesn't buck or surge. Shifting rpm falls quickly but still holds at 1200-1300 rpm's at a red light for 3-4 seconds. This is the best I have got it to do in the last 3-4 months. I have tried to set the idle at least 6 times using all sorts of advice off the forums, this one, Corral and others. This computer is killing us.
 

PonyBoy94GT

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Can you prevent it from stalling by not pushing in the clutch and coasting as you come to a stop. Maybe downshift to slow down then stop.

The Speedo/Odometer is working normally?
im very curious about this. my car has had and issue for a bit now of doing this exact stalling thing. my speedo works and tach but the odometer and trip meter dont. this could affect driveability?
 

cobrajeff96

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Doesn't the speed signal get used by ECU to keep the engine alive despite zero throttle input (TPS)?

I know in the later model engines (Coyote) they call it "Torque Decel" and it was causing gen1 swapped cars to have the same problem until they used original VSS wiring to communicate a speed signal into the control pack harness/computer. Maybe there's a pinched or broken wire somewhere in that circuit leading to the ECU in your car.

I think how it's supposed to work is that a small bit of idle hang occurs when TPS goes to zero so the car doesn't stall when coasting to a stop, and then even after stopping there is supposed to be a few seconds of idle hang.
 

LEGALLYFAST

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Have you checked for any other vacuum leaks? I would recommend getting a smoke machine. You could be diagnosing and have a different issue. At least this will verify you have no other leaks. Those plastic lines are nortorious for breaking.
 

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