mybaby89

I've got an '89 GT with the 5.0 H.O. in it. About a month ago I droped a rebuilt 5.0 H.O. motor into my car. I have had some problems since than. At first when you went to start the car in would not want to run on its own if you were to put it in gear without hitting the gas it would die. To stop at lights or stop signs you would have to put the car in Neutral and keep the rpms up so it wouldn't die. (Yes the timing is right) It acts as if it is getting too much fuel and not enough air mixture. I have replaced the following items with very little change. Mass Air Sensor, Idle Air Control Valve, 2 New O2 sensors, and glass packs. I forgot to mension there was no exhaust to start with. (I had to cut it out to replace tranny.....its a long story) As of right now when you sart the car it will run on its own for the first 15 seconds at 1500rpms as soon as it high idle kicks off it will die. once the car is warmed up it will stay running, but it still doesn't seem to be running right. once the car is warmed up you no longer have to put the car in neutral to stop. it will run on its own. The only 2 things I can think of right now that could be the problem are. #1. not enough back pressure from the exahust. it is just running headers-cats-into the glasspacks and out. the exahust stop right behind my frount seats. #2 The kick down still needs to be adjusted cause the car want to shift too soon, but i don't see how that would effect the cars idle. this is my problem and the only thing keeping me from driving my baby anymore. its too much of a pain to have to sit in the car in the freezing cold to get it started just to drive 5 miles to work. So if anyone has any ideas please let me know. My brain is fryed at this point and my friends and i are out of ideas. Also does anyone know the correct way to adjust the kickdown, or know where i can find out. for some reason my chiltons manual is not very good at telling me how. thanks for the help.

1993mustanggt

my brother had an idling problem in his 94 cobra and it ended up being something wrong with his idle air bypass in his throttle body. i dont know if this will help but its maybe something to spark a thought.