I can't get rid of code 0106 MAP sensor code on new build
 

I built the engine in our 2001 C5. It's stock cubes with Eagle rods, Probe pistons, ported 241s, COMP XER 281 (232-234 / .595"-.598" 112 LSA), COMP 850 lifters, LS6 intake, ported throttle body, 42# injectors, long tubes, high flow cats, axle back exhaust, and A.I.R. delete.
I initially had a mail order tune done. The car was running extremely rich. I had a friend retune it so it would idle and wasn't dumping fuel. Now, I have a 0106 code that won't go away, which is "MAP or BARO pressure CKT out of range". My MAP reading is 18.1 HG and 2.7 volts.
I changed the MAP sensor and checked the connector/wires. Got it back together and it made no difference. If I clear the code with the car running, it won't kick the code until you shut it off and restart it. Mt "freeze frame failure data" shows it was at 19.0 HG and 2.84 volts. The engine is pulling 12" of vacuum at idle.

Frank

If no response here, try the PCM Diagnostics & Tuning section.

My car did something similar and my tuner adjusted the performance range of the map. He made the lowest range 0 and highest 100 I believe and I've had no issues since