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. My "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

 

Just turn the code off. It is looking for the predicted MAP reading that would be produced with a stock cam. You don't have a stock cam. The MAP sensor is working isn't it? Why care about predicted MAP on a modified car? There are P0106 Predicted Min and Max tables you could adjust to try and satisfy the diagnostics but it is easier to just turn it off. P0106 is not even enabled from the factory on 97-98 LS1 cars.

 

P0106 is a common code with a cam that raises the idle Map. You need to raise the P0106 Error Map Calculated Max table to be higher than your actual Map pressure vs RPM & Map.

Look at a ZO6 table, should work perfect for your car.

Russ Kemp