Car Sputters And Dies At Idle Help

01BullittBeast

New Member
Jan 28, 2014
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I have a 2001 Bullitt mustang, 4.6L SOHC. The car sputters a little then when I press down the pedal it clears up. When coming to a stop the car dies out. When I start the car back up it dies again unless I give it gas. Usually only happens when the engine has been warmed up. I've replaced IAC, TPS, EGR valve, EGR vacuum regulator, DPFE sensor, Crank position sensor. I've cleaned my air filter, MAF sensor, throttle body, and intake. I've checked for vacuum and exhaust leaks, none. Checked oxygen sensors, readings within spec. Fuel trims are a little high. Replaced spark plugs. Rebuilt injectors. Cleaned fuel system. New fuel filter and fuel pump. Ohm tested coils, all are good. Idle set screw is a base idle. No smoke from exhaust. Intermittent misfire code on cylinder 6. No other codes. Stumped on problem.
 
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Mattstang04

10 Year Member
Sep 15, 2006
1,143
141
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St. Louis, MO
I would first, check the plug and coil on number 6. Fix as necessary and get that code out of the way.

Then, my next question would be what brand of IAC did you put on?

People have a lot of problems with anything but Motorcraft IACs for some reason. These cars seem to reject aftermarket IACs.
 

01BullittBeast

New Member
Jan 28, 2014
6
0
2
36
Fuel pressure is in spec. Brand new fuel pump, fuel filter, fuel rail, fuel rail pressure sensor, and rebuilt injectors.

Plug in 6 looks normal, I've swapped plugs around to see if I had a bad plug and misfire is still in 6. Coil boot has no cracks, moisture build up, or arcing. I ohm tested all the coils and all within spec. I've swapped coils around and misfire still in 6.

The IAC is from NAPA. Delphi or Echlin brand. I'm almost thinking I got a bad one out if the box and the car doesn't like it.