91 mustang idle surging

Theekinghumpy

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Jul 3, 2019
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Indiana
I have a 91 mustang gt with a 93 motor in it with some work done to the motor from what I was told. They said it had a cam in it, 24 lb injectors, trickflow intake, 93 computer and bbk headers. There might be more but I'm not aware of but I sent it into a mechanic that had to use the 93 harness to get this thing running. So the car starts right up but idles up and down and the exhaust smells like gas bad. Anyone have any ideas where to start?
 
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I was told it was calibrated to the 24lb injector. Can't confirm that
 

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Can't tell much from that picture... it kinda looks like a 93 cobra 70mm maf though. I'd removing, measure it and cross reference it with pic's of a 93 cobra maf. Have you dumped the codes??? Search for the "Idle Surge Checklist" thread... it will get you dialed in.
 
Make sure you have the right computer for the 02 sensor harness that is in the car. The 02 harness between the automatic and the manual are different. If you have an A9L, A3M in there you need the 02 harness from a factory 5 speed car. If you have the A9P or C3W you need the automatic harness. If you run the auto harness with one of the 5 speed computers you will fry it and possibly cause the 02 sensors to not work. This would cause it to run rich...extremely rich.
 
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