Engine Mechanical problem
1998 Chevy Cheyenne V8 Four Wheel Drive Automatic 197000 miles
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when the truck warms up 2500 series 4x4 chevy the engine idles rough. sometimes when acceralting it dogs. when it is cold it runs great. runs great when running down the highway. no smoke not bad fuel milage.

Is the SES light comming on yet? It sounds like the ECT(engine coolant temp) sensor, with engine cold read the ohms across the sensor, then read again when warm, cold it should read over 10,000 Hot it should read 177. If the SES is on go to Autozone and get the codes read, they do it free, post the codes here.