2003 chevy silverado 1500 hd 4 wheel drive

This truck has been a good running truck until recently… lately you can drive for awhile then the check engine light comes on… readout says reduce engine power… if you stop for like 30 seconds or less and restart all is fine . it doesnt do this all the time or every time has done it once a day or 4 times in a row, never a rhyme or reason to it. I have used my computer reader to see if i can find the problem myself but for some reason the reader cant read ( still trying to trace why… even the free scan from oreillys couldnt link to my onboard computer for some reason) so here i am asking for help, does anyone have any ideas as to the problem or to the onboard computer not linking to any reader?

Check the fuses, the cigar lighter fuse also provides power to the data link connector.

ok that helped!!! we got a reading that was a map sensor also had a code for throttle position sensor input too high and another for throttle position sensor input to high so we cleared all will see what happens when i drive it tomorrow…

When the codes come back, post the exact and specific codes in the “Pxxxx” format.

And do not just start replacing parts.

p0101 ( mass air flow) p0122 (throttle position sensor voltage too low) po123 (throttle position sensor voltage to high) then when i had oreillys read it they came up with two more but they didnt give me the codes… something about fuel bank 1 and fuel bank 2… remember when the stupid thing acts up it goes to reduced engine power I dont kknow if that would throw anything off… ok ready for any help or it goes in on wends!!!they guy at oreillysthinks its a sensor somewhere and could be throwing the other things off to make them code??