1999 GMC Suburban Fluctuating idle

1999 GMC SUBURBAN
800 MILES • V8 • 2WD • AUTOMATIC
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CPREVO
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I recently had my engine overhauled, changed oil after 500 mls. Started idling in drive at stop lights etc... At 400 to 800 rpm. Truck lurches forward on the way to the 800. Place it in park or nuetral and it is fine. If ac is on... Turn ac off and it stabilizes but comes back within a minute. Rplcd idle air control motor, position 2 pre catalytic converter o2 sensor.cleaned throttle body. Cleaned mass air flow indicator, cleaned iac valve, flush injectors. Resest computer on vehicle.... Still happening.... Any other ideas? I did replace the fuel pump about a year ago.
Jun 13, 2010 at 11:31 AM
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RASMATAZ
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Test the throttle position sensor and manifold absolute pressure sensors to include the fuel pressure
Jun 13, 2010 at 4:47 PM