I just bought my mustang off a guy who has done a lot of work to the car and I think a lot of bad. I have hooker header running exhaust all the way back with no 02 sensor ports no cats ,nothing. I lways have the check engine light on and cant even get a sticker for the car. First gear is soo damn slow and raises the rpms soo high i think the car is gonna blow up on me. the car came wiht a sct tuner that has been noted to be out dated and none of the tunes on there work . I dont think the tuner was for this car. for a v8 i think the car should have some heart. PLEASE someone e-mail me at [email protected] and tell me what i should do. the idle hangs and i already replaced the iac. just bought a new tps but dont think that is the issue. i know nothing about mustangs and really need some help.
I'm assuming this is an automatic. Is the speedometer accurate? An inaccurate speedometer can mess up the automatic shift points. But if looking for an educated guess it takes time for an automatic to shift gears. The PCM must call for the shift BEFORE it is actually needed. When lower gears are used the RPM's will climb faster. Therefore the shift points will need to be lowered to account for the faster RPM rise so that the shift will actually occur at the correct RPM's/time.
Here's some information on how to trouble shoot Idle/IAC issues.
Have mercy on you for trying to correct another man's "hot rodding". Re-virginizing a car is a daunting task. The old cars, before miles of wiring played an integral roll in vehicle function, They were easier to put back to stock. All the gadgetry and electronics of modern or even semi-modern cars complicates the "un-screwing" of them.