Installed a new boost control solenoid, and I am now getting up to 8.84 psi of boost (I bought an LS1M scanner from a BF member about a month ago). Based on everyone saying I should get 7 to 9 on a stock set up, it looks like my boost issue is resolved.
Todd, I did check out the MAP sensor and it seems okay. I unbolted it from the engine, pulled the vacuum line off, and left the electrical connector on. I used my MitiVac to applied a measured vacuum, and with the ignition on, engine not running, I used my scanner to tell me what manifold pressure the MAP sensor was detecting. The reading directly matched the vacuum I was applying, so it looks like the MAP sensor is functioning properly.
I am getting some KR under boost, but I will start a new thread for that.
Thanks all for your help.
2001 Bonneville SSEi (retired at 365,000 Kms.)
2014 Jeep Grand Cherokee Overland (yes, I know its not a GM)