Ford Repair: Newly moodified engine, ford mustang gt, mass air flow

Question
Steve I so hope you can help I am seriously at the end of my rope. I have a 93 Ford Mustang Gt and have recently put a brand new modified engine in it going from a 302 to a 347. The problem I am having is an irratic idle when starting, for the first few minutes it will idle good and then it starts bouncing all around. It will straighten itself out but as soon as you shut it off and restart it again it does it all over. I am 42 years old and have been a mechanic all of my life, these are the things i have tried twice with no prevail: drilled a quarter inch whole in the throttle body, set the TPS to .999, new fuel pump, filter, plugs, and wires, tried hanging the air charged sensor over the side of the engine plugged in, checked three times for vacume leaks, put all new vaccuum hoses on it, adjustable fuel pressure regulator set at 42lbs with no vaccuum, Everything is brand new from top to bottom. THis is what i installed Trick flow heads, Trick flow upper and lower intake, BBK 70MM throttle body and EGR, 30Lb injectors, 76MM C & L mass air flow calabrated for 30Lb injectors, 225 LPH Fuel pump, Trick Flow Stage two Cam, If you have any suggestions or comments please email my wife right away I just want to be able to sleep at night again Thanks so much for your time!

Answer
John-

  I honestly think this problem can be summed up pretty easily.  My guess is that at .999 volts your TPS is just too close to the 1 volt that starts to alter fuel and timing.  My guess is that if you dial it back to around .990 or better yet .980 that your idle will stop hunting.  Besides, I've done some testing on TPS settings on the track and, while the car feels stronger (.970 vs. .980), I did three runs at each setting and all 6 runs were virtually identical.  If readjusting it doesn't change anything, please get back to me and we'll go from there.  Hope this helps.

Steve