running only in

  1. M

    Electrical 1989 mustang 5.0 runs rich and stumbles in closed loop

    So I recently converted my 1989 4 cyl to a 5.0 using all the correct engine harnesses from a 1989 car. The ECU I'm running is the A3M out of a 93 car. So the car starts right up no problem. After let's say 60 seconds of idling the car from what I think goes in to closed loop and once it does it...