Boosting for no reason

[marek4792]

Are your sensors all new? IMAP, Exhaust Pressure, EGR Differential pressure sensors? I asked because I had a CM870 with the air powered VGT and it would build 35+lb's of boost with my foot barely on the pedal and then the next time would be okay. While the boost would spike under load, the engine would choke itself out and slow you down blowing a big cloud of black smoke behind you in the process. If you hold the pedal too long the turbo will "chuff" violently until you back off the pedal. Granted a CM870 is a different animal then the 871, but it definitely is turbo/egr related especially if it does it intermittently.