2001 Pontiac Grand Prix Loss of power on my GTP

2001 PONTIAC GRAND PRIX
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ECOSME74
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Engine Performance problem
2001 Pontiac Grand Prix 6 cyl Front Wheel Drive Automatic

Fixed the MAF Sensor, cleaned the EGR, changed spark plugs and wires. The car runs fine. Problem is when you accelerate to pass another car the motor starts trembling and looses power as if it were choking. I know its not the limiter, there is no exact RPM for the misfire or what ever is happening. When put in a fast acceleration it chokes and trembles, gains power and looses it again in different intervals. If you dont push it hard it runs fine. Has no check engine light on. Im tired of "repairing" different things and the car remains the same. Could it be the ECM, PCM, Supercharger or something else?
Nov 28, 2009 at 9:39 PM
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MMPRINCE4000
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Start by measuring fuel pressure with mechanical gauge. Check the fuel pressure regulator for gas in vacuum line.

Are you getting any boost?
Nov 30, 2009 at 7:29 AM
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ECOSME74
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Between the intervals of the misfire you can feel the supercharger boost but then it cuts to the misfire and so on. Ill be checking the fuel pressure this week, thanks.
Nov 30, 2009 at 7:58 AM
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MMPRINCE4000
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Let me know what you find. If FP is OK, then you have a ignition problem.
Dec 1, 2009 at 7:57 AM
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