[SOLVED] Engine Refresh and now codes

ENGINE/DRIVABILITY
Year/Make/Model: 2007 Mazdaspeed 3
Mileage: 207,000 miles
Location/Alitutude: Missouri Ozarks
Concern: Engine will not idle, or occasionally will hang on with a very rough idle, then die; when rolling slow in 1st or 2nd gear, gas pedal is VERY touchy and causes the car to buck; Engine bogs/misfires? once turbo starts to spool (>5psi),
DTC's: PCM: 2177(fuel system too lean at off idle), P0571(cruise control/brake switch A circuit malfunction), P0403(egr deleted), IC: U2064
Modifications: Mazdaspeed Intake, 2"ish Turbo Inlet pipe, stock replacement turbo, Ebay Downpipe (12 years old and still in great shape!), Autotech HPFP, Aftermarket top-mount IC(unsure of brand), aftermarket BPV, Grimmspeed EBCS
ECU/Tuning Software: Cobb Accessport V3, tried 3 different basic tunes, including safemode with no difference
Tuner: n/a
Is the concern intermittent? No
Can you duplicate the concern? Yes
Recent Repairs: Replaced rod bearings and rings on 4 pistons, deleted balance shaft anchor(!) and installed plug, reinstalled recently replaced timing parts (chain, VVT, tensioner, etc), new Autolite iridium spark plugs gapped to .028
Attempted these corrections: Cleaned intake flapper, MAF, and purge valve
Correction: Found untorqued intake bolts using spray and search method; torqued intake bolts and all is well!

 

You probably have a really bad vacuum leak. You need to check for any and all possible air leak locations (turbo pipes, post MAF sensor pipes, intake manifold, vacuum hoses, brake booster pipe)

Get a can of brake clean and spray suspected areas. If the car idles up suddenly you may have a leak there.

 

**Update and correction!
Thanks for the suggestions. I used MAF sensor cleaner spray at all hose connections and then I got a reaction over the lower part of the TMIC. Voila. I thought I had a leak in the used TMIC, but after replacing it with the stock intercooler, there was no change. I pulled the intercooler off again and did more searching, and surprise, I didn’t torque down the intake bolts!
Yep, the idle issue and p2177 code was due to it pulling air through the intake gasket. I’m an idiot, but spraying flammable liquid all over this potential dumpster fire help save my sanity.