Illumination of the Check Engine Light can be caused by a loose or worn gas cap.Google+
Car Problem Reports
Chevrolet Silverado 2500 HD Check Engine Light Due to Gas Cap Issue
Chevrolet Silverado 2500 HD Problem
Exhaust & Emissions Affected: Gasoline
Average Mileage: 80,658 mi (43,000 mi - 173,000 mi)
Visitor, 2006 Chevrolet Silverado 2500 HD, 86,000 mi
CHECK ENGINE LIGHT COMES ON THE IT SAYS TIGHTEN FUEL CAP ON THE DASH
Visitor, 2006 Chevrolet Silverado 2500 HD, 43,242 mi
Check engine came on when engine was started . Did code check... it said evap problem . Gas cap o ring showed light wear . Installed new cap and cleared code ... check engine light off on restart.
Frustrated. I have a 2500HD 6.0 with 173,000 mile. Never a problem until now. The check engine light came on, so I had it diagnosed and the code said bad fuel cap. I also informed the mechanic that I don’t have any very little power at take-off. The mechanic said it could also be the catalytic converters are plugging up. I replaced the catalytic converters, which seemed to change the power issue. However, I still have the engine light stating a bad fuel cap. WTF. I removed the fuel cap and the truck starts and runs normal. However, now, when I fuel up the truck, it doesn’t want to start and it takes several cranks to start, and then it sounds flooded.
I don’t know where to start. The truck runs fine until I fuel it up, and then it takes several attempts to start the engine.
Visitor, 2005 Chevrolet Silverado 2500 HD, 50,736 mi
gas cap turns engine light on...