2003 Chev 2500HD - 6.0L Reduced Engine Power

[posttire]

I have a 2003 Chevy 2500HD 6.0L here that came in with it going into reduced engine power.

Customer has had it at the Chevy dealer, they applied dieelectric grease to the TAC module, replaced the brake switch for cruise control, and installed updated software. Then he took it to another shop and they replaced the connector and approx 12" of the wires for the TBI unit, and replaced the ignition switch, and the pedal sensor. It came in with the following codes P0300, p1125,p1516, p2120, and p2125. We are not sure where to go frm here.

Any suggestions??

[ricmorin]

I'd identify which code(s) failed this ignition. The factory scanner gives you this information. Not sure which aftermarket one does. Then delve into that code/cause. If I couldn't determine that, clearing and driving until something set would be my next approach.

[brianp87]

I'd identify which code(s) failed this ignition. The factory scanner gives you this information. Not sure which aftermarket one does. Then delve into that code/cause. If I couldn't determine that, clearing and driving until something set would be my next approach.

Great start.

[Tim Martin]

Along with checking those codes, I'd also be checking the fuel pressure, just to make sure. But there well could be an issue with the APP and/or the throttle body. Another thing you'll want to check is the 5 volt reference wire to the APP sensor.

[posttire]

Thanks for the info guys. I hope that one day I can repay the favor.

[steven kiser]

i work on a lot of gm's and see a lot of power loss issues relating to a fuel issue. it's about the age of a failed pump. i'm not saying just throw it at it but it's the first thing we look at it. i've had vehicles brought in with all sorts of replaced parts only to find an original filter and low pressure. the pumps in these will waver and stumble, if i find the pressure is even a lb below the minimum i replace it. for some reason i find a lot of vehicles that haven't had the filter replaced and they're rotted solid. years ago i purchased a dorman fuel line repair kit and now don't even mess with the lines if they're all knarley and rusted.