Could be the Charge Motion Control Valve and Intake Manifold Runner Control, CMCV / IMRC. It runs on vacuum I believe. If it's stuck in the wrong position then it would affect the idle.
I was referring to the intake manifold not the tube. It's possible if it was off at some point the gasket could be pinched. Also, I see the car has headers, do you still have the cats? Could be O2 sensors, but that would throw a different code maybe.
Sounds like a vacuum leak, hence the P0171 code, but you did smoke test it. Make sure that the CAI coupling to the throttle body is fully seated and the clamp is tight. The throttle body sits downstream of the air flow sensor and any air leak after the fact will cause a lean condition. Also try...
I have a hard time believing the pads are toast at 37K miles. However, I've changed pads many times without doing the rotors. The only time I change rotors is if they are worn, i.e. deep grooves or warped, which you will feel in the pedal as pumping. Take a look and see if the pads are worn...
It's normal after replacement. You need to rachet the hand brake numerous times to get the pistons to move out. Also as you drive and use the brakes it will also rachet out but will take longer. Or you can take the wheel off, find the E brake level and rachet it there.
The average person, who wants a Mustang, will walk into a dealership, see the price of a DH and gasp. Said person will lower his expectation and walk over and start looking at GTs. Maybe that person can afford a GT, maybe not. On the way out the door, all of a sudden the EBs start looking good...
While it is cool, and I applaud the effort, to me, it still will look tacked on and not integrated in the dash. If it was say 10" and fit within the dash's bezel then you would have something.
If your pay did not keep pace with inflation, then the sting of a $15K price increase is painful. I can only speak for myself and say my take home pay did not keep pace. And don't get me stated on how the hell my house for tax purposes is evaluated $72K more than last year!
What did I do today, let me see, I attempted to dig both my Mustangs out. Yes there are 3 cars in that snow drift somewhere. I figure they'll see daylight by Thursday. RI broke the record for the most snowfall ever. 32" - 36".