I built a factory five roadster aka cobra using the drive train from a 1996 mustang GT. I'm using a 4.6L SOHC engine with 5 speed manual transmission. I am using the stock EFI system. The engine runs great, but sometimes, once it is warmed up, it stalls when coming to a stop. It starts right back up, and otherwise idles fine.
The engine setup is very basic. I rebuilt the engine after having it round bored, and installed new pistons, rings, and bearings. I have custom headers with side pipes. The heads have after market "mild" camshafts by comp cams. Some people refer to them as RV cams. I am not running CATS or EGR. I don't have power steering or power brakes. All sensors - O2, cam, crank, MAF, IAT, TPS, - are new. The IAC valve is also new, as are the plastic intake manifold, fuel pump, fuel filter, and fuel pressure regulator. I even installed a new rebuilt/reprogramed PCM. I am confident there are no vacuum leaks. My TPS voltage is .96 at idle. I have an SCT tuner from BAMA, and had the idle set high (about 1000) in an effort to minimize the stalling issue, but it still stalls occasionally. Because I don't have power steering or power brakes, the stalling is really not that big an issue, but I would like to fix it anyway.
Does anyone have any suggestions on how to fix this issue? I know it sounds like a vacuum issue, but I'm confident there aren't any leaks. I did a smoke test. I have fiddled with the Throttle body stop screw - yes, I know you are not supposed to do that - but am pretty sure I have it reset correctly, creating a .010 gap, then turning it in a half turn. I also modified the TPS so it is adjustable. I'm wondering if I were to rotate the TPS a little, to bring the voltage up to about .99 if that would make a difference.
Any suggestions are appreciated.
Thanks
The engine setup is very basic. I rebuilt the engine after having it round bored, and installed new pistons, rings, and bearings. I have custom headers with side pipes. The heads have after market "mild" camshafts by comp cams. Some people refer to them as RV cams. I am not running CATS or EGR. I don't have power steering or power brakes. All sensors - O2, cam, crank, MAF, IAT, TPS, - are new. The IAC valve is also new, as are the plastic intake manifold, fuel pump, fuel filter, and fuel pressure regulator. I even installed a new rebuilt/reprogramed PCM. I am confident there are no vacuum leaks. My TPS voltage is .96 at idle. I have an SCT tuner from BAMA, and had the idle set high (about 1000) in an effort to minimize the stalling issue, but it still stalls occasionally. Because I don't have power steering or power brakes, the stalling is really not that big an issue, but I would like to fix it anyway.
Does anyone have any suggestions on how to fix this issue? I know it sounds like a vacuum issue, but I'm confident there aren't any leaks. I did a smoke test. I have fiddled with the Throttle body stop screw - yes, I know you are not supposed to do that - but am pretty sure I have it reset correctly, creating a .010 gap, then turning it in a half turn. I also modified the TPS so it is adjustable. I'm wondering if I were to rotate the TPS a little, to bring the voltage up to about .99 if that would make a difference.
Any suggestions are appreciated.
Thanks
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