My car is really starting to stump me, it is a brand new engine with 334 miles on the clock and hasnt run right the entire life of it. the car always hesitates no matter what, i give it gas and it doesnt even have its full amount of power and barely responds. i have replaced the fuel filter, pump, ignition coil, tfi module, checked for vacuum leaks, had it tuned, timing set to 12*. The car runs really hot. then the other day it was still hesitating and such but then i shut it off, had lunch and went to go home and it started running really bad, it would not keep a steady idle on the tach, the tach was flying EVERYWHERE. ive never seen it fly around so much. the idle was not really changing though. it is also pulling low vacuum for some reason, about 10 pounds and also backfires when it gets hot and i let off the gas. it is supposed to be 440hp at the crank and it is real far from that. it has the tfs stage 1 cam so im not totally sure what timing is supposed to be at. please help someone i really wanna drive this without having to worry about it breaking down and this annoying hesitation, thank you everyone.