1988 Mustang gt runs rough when below 2500 rpm when motor is cold - Ford Mustang Forum
 
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post #1 of 4 (permalink) Old 12-04-2009 Thread Starter
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1988 Mustang gt runs rough when below 2500 rpm when motor is cold

car runs strong but when the motor is cold with the computerized choke on it runs rough. when the choke turns off it runs perfect. if i have the fuel pressure to high could that be the problem. what should the fuel pressure be any way? if i lower the fuel pressure it seems like i am lossing power.... but.... its seat of the pants feeling. never been on a dyno. any ideas?

1988 GT Hatchback, 5 speed, BBK Headers, BBK H-pipe, Flowmasters, 3:55's, Subframe Conecters, Underdrive pulleys, BBK Cold Air, 65mm throtle body, 70mm TB spacer, 70 mm Mass air, 93 Cobra ECM, Mass-Air Conversion, 24 lb injectors, B303 cam, ported and polished upper and lower intake and ported and polished heads, heads shaved, total rebuild.

this was the old time....
1/4 mile..... 14.10 @ 95 MPH before i went into the motor.... on street tires.......
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post #2 of 4 (permalink) Old 12-04-2009
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by computerized choke i guess you are referring to open loop/closed loop operation. when your motor is cold your computer operates on presets, not off of 02 sensor and other sensor feedback. if it runs fine once it hits closed loop (sensor feedback) operation then it could possible be a result of your mods if you have never had it tuned. whatever is going on is bad enough to make it rough at start up but slight enough that the computer can compensate for it by itself once in closed loop. hope that helps you narrow it down!

1988 GT

ASE certified technician
(5 of 8 so far)
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post #3 of 4 (permalink) Old 12-04-2009
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Sounds like a job for the tuneup man
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post #4 of 4 (permalink) Old 12-05-2009 Thread Starter
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what is the best way t g abut getting it tuned? buy the software for my laptop r get a chip burnt. or where can i take it to? and what kind of money am i looking at?

1988 GT Hatchback, 5 speed, BBK Headers, BBK H-pipe, Flowmasters, 3:55's, Subframe Conecters, Underdrive pulleys, BBK Cold Air, 65mm throtle body, 70mm TB spacer, 70 mm Mass air, 93 Cobra ECM, Mass-Air Conversion, 24 lb injectors, B303 cam, ported and polished upper and lower intake and ported and polished heads, heads shaved, total rebuild.

this was the old time....
1/4 mile..... 14.10 @ 95 MPH before i went into the motor.... on street tires.......
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