Noises problem
2000 Chevy Venture 4 cyl All Wheel Drive Automatic 89000 miles
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my van is idoling really high when put into park. at times from a complete stop it idole speed can reach 60km without touching the gas. as well when we are on longer drives and happen to need more power to go up hills or to excellerate when the gas pushed there is no power what so ever. many times if we are faced with this problem we turn the van off and restart it and it often corrects it self for a period of time.

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.