Engine idle

GMC C2500
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TOMHEP
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I have a 1990 GMC 2500 Sierra with automatic transmission and 350 engine or 5.7 with 50,000 miles. I just replaced the engine and when I started it it will not idle but runs at about 4000 RPM's. What wrong?
Nov 17, 2007 at 5:46 PM
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RASMATAZ
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Check the idle air control valve and throttle position sensor
Nov 18, 2007 at 7:41 AM