1997 Pontiac Bonneville high idle in drive


Engine Performance problem
1997 Pontiac Bonneville V8 Front Wheel Drive Automatic 95800 miles

reprogram the computer, new idle air sensor, tps sensor idle good, driving itdown the road, take foot off the gas pedal, car due 30 mph, put in park, fast idle is on.3800 pontic engine. Also clean all grounds. Tkx

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have the same problem?
Tuesday, April 7th, 2009 AT 2:14 AM

1 Reply


Too fast an idle speed. If an engine without computerized idle speed control is idling too fast and refuses to come down to a normal idle speed despite your best efforts to back off the carburetor idle speed screw or air bypass adjustment screw (fuel injection), air is getting past the throttle somewhere. Common leak paths include the carburetor and throttle body gaskets, carburetor insulator spacers, intake manifold gaskets, and of course, any of the engine's vacuum fittings, hoses and accessories. It is even possible that leaky O-rings around the fuel injectors are allowing air to leak past the seals. Another overlooked item can be a worn throttle shaft and a defective idle speed speed control motor/valve stuck in the extended (high idle speed) position/throttle position sensor. Also the throttle plate could be binding in its bore and kinked accelerator cable, coolant temperature sensor might not be operating properly misleading the computer that the engine is still cold and computer throwing fuel at it raising the idle speed.

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Tuesday, April 7th, 2009 AT 2:24 AM

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