i just bought my first mustang it is a 89 gt with a 5.0 and a t5. i am having a little problem. when i accelerate with half or three quarters of throttle it pulls nicely but the second i put it all the way the the floor if feels like it bogs out. also in the morning when it is cold it hesitates really bad but only for about a half mile then it good . but the full throttle problem always happens. the car has headers, catted H pipe, flowmaster cat back and a under hood cold air intake, all that stuff was on it when i bought the car and it has been doing it since i bought it, there is no check engine light on. if any body can help me i would greatly sppreciate it. thank you brian.

 

Does it have a MAF after the air cleaner?

 

Check the timing, I had the same issue and found I was grossly retarded.

 

i did the timing it was on 10 i bumped it up to 15 with no pinging. the maf is in between the cleaner and the tb.

 

check for codes anyway if the check engine bulb is burned out. It happened to me.

 

i will check 2marrow for codes thanks for all the help if anybody has more ideas please help thank you.

 

LMAO!

I couldnt help it!