I have a 2001 Mustang 3.8 v6. I have recently rebuilt the motor. All new parts. I have a 273Grind Cam (http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=838&sb=2) , Shaved stock heads, Bored 0.030 and the Lifters AND Valve springs that go along with the cam. Thats about it. The car idles fine, but when you press the gas and get it to about 3.5-4k RPM it wants to bog down, now i know the newer mustangs have a rev limiter on them to only allow them go to go 4k or so on. but it starts to bog down right before it hits 4k. the MAJOR problem is when i go to put the car in gear and go it does it VERY bad at 2.5k RPM, The car has sat for about 4-6 months before i rebuilt the motor. New gas was added (93). IF ANYONE, has any ideas or solutions to my problems or any QUESTIONS about what else i could have done to the car please let me know, Thank you.

 

Have you tested your throttle position sensor?