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mustangman4 · 12-30-2003, 09:23 PM

The cam is what is causing the hunt for idle. There is now more fuel needed to ignite the flame but at idle the IAC valve can only handle so much. So when a lope in idle occurs the only thing the ECU knows to do is to turn the IAC on but now with the cam when it trys to control idle it goes way too far and the ECU see the jump in MAF voltage but never sees the TPS sensor voltage rise it doesnt know what is going on. What it comes down to is you now need more air at idle for the amount of fuel the motor needs. A custom chip does alleviate some of the concern in fact you are at the same point a lot of people are at when they do the heads cam and intake on the car. If you have a aftermarket throttle body look at the throttle plate. Does it have a hole in the throttle plate? If it doesnt look at your stock throttle body it will have a hole in it. Now drill a hole in your new one a little bigger than the stock one is but in the same spot. Also make sure your throttle plate is closed at idle. This will or should help the stalling when coming to a stop. This will make sense to you because that is what the vacum leak was doing for you letting in more air. The hole will act as an uncontrolled IAC valve. The hunting and surging at cold start. A chip will help. I use PMS from Anderson Ford/EFI systems. Pulling a little fuel out of idle helped me out and it may do the same for you. Just something you can request from a chip company when you order a chip. If you would like one let me know I have one from my old setup. It fixed some of the idle surging and the buck and jerk you may experience going down the road at 1500-2000 rpms cruising. Hope this helps.

Brad

12-30-2003, 09:23 PM	#2
mustangman4 Registered Member Join Date: Feb 2003 Location: Oshkosh WI Posts: 69	The cam is what is causing the hunt for idle. There is now more fuel needed to ignite the flame but at idle the IAC valve can only handle so much. So when a lope in idle occurs the only thing the ECU knows to do is to turn the IAC on but now with the cam when it trys to control idle it goes way too far and the ECU see the jump in MAF voltage but never sees the TPS sensor voltage rise it doesnt know what is going on. What it comes down to is you now need more air at idle for the amount of fuel the motor needs. A custom chip does alleviate some of the concern in fact you are at the same point a lot of people are at when they do the heads cam and intake on the car. If you have a aftermarket throttle body look at the throttle plate. Does it have a hole in the throttle plate? If it doesnt look at your stock throttle body it will have a hole in it. Now drill a hole in your new one a little bigger than the stock one is but in the same spot. Also make sure your throttle plate is closed at idle. This will or should help the stalling when coming to a stop. This will make sense to you because that is what the vacum leak was doing for you letting in more air. The hole will act as an uncontrolled IAC valve. The hunting and surging at cold start. A chip will help. I use PMS from Anderson Ford/EFI systems. Pulling a little fuel out of idle helped me out and it may do the same for you. Just something you can request from a chip company when you order a chip. If you would like one let me know I have one from my old setup. It fixed some of the idle surging and the buck and jerk you may experience going down the road at 1500-2000 rpms cruising. Hope this helps. Brad __________________ 93 GT 306 DSS, O-Ringed, AFR 185's, Pro Products Intakes, 55lb low imp inj, 80mm Pro-M meter, 2004 PMS, AFM Power Pipe, Kirban Reg, Vortech S-Trim 14lbs. No times yet. Trying to tune.