reduced engine power on 2003 Chevrolet Silverado 2500 HD

I have an 03 chevy 2500hd and the reduced engine power light came on and the throttle dont work it happened the other day and I just let it idle for about an hour and it worked. It happened now and it wont straighten out and it runs rough it will only rev up a little bit now?

Asked by for the 2003 Chevrolet Silverado 2500 HD
try looking at the throttle body wiring 8 pin connector one of the wires could be broke or open in circuit
1 more answer
I just bought the same truck and it did the same thing to me the other day. I turned it off and on three times and it went back to normal. The truck seems to crank over slow so we check the battery and found that it was only at 10 amps. The bought a new battery and the problem hasn't come back since. Check your battery with a meter. This may not be the correction, but has been fine with mine.