Reduced Power 2004 2500HD 8.1L Gas

[Squatcher]

Hi, Richard from Pleasant Lake, Michigan.

 

I have a 2004 Chevy 2500HD with the 8.1L Gas, with 44796 mileage, but 7400 hours on the engine. I bought this used from a dealership over a year ago and am now having issues with the truck. I have been having problems with the Yellow Engine symbol showing up and Reduced Power showing in the DIC window. Plus I am hearing what sounds like predetonation/ rattling from the engine when I give it gas. The engine runs ok, but there is more to the noise than a smooth running engine, kinda like a rumbling.

 

Can anyone help me figure out what is causing this?

 

I have had this happen three times so far, once during the summer of 2013, once last December and yesterday 1/19/2015. When it occurred back at the end of December I pulled three codes from my truck.

 

P0220

P0134

P0300.

 

When it occurred last summer, I changed all the plugs and wires to AC-Delco.

 

I found out that if I start, run for a minute and shut down several times, the error goes away and I'm ok. I just need to get this resolved, because I use this to pull out travel trailer.

 

I have run a couple of tanks of premium thru it and added cleaner to the fuel previously.

 

Thanks,

Richard

 

2004 2500HD, 8.1L Gas

 

 

 

 

[02suburbanZ71]

Richard. You really need to see a mechanic, sorry.

[kstruckcountry]

Check throttle position sensor, replace left upstream O2 sensor to start.

[oldscsc]

x2 on the TPS sensor diag. Don't just throw a sensor at it. Verify you have a proper ground, 5V reference signal, and signal output is smooth and linear.

[Squatcher]

Sorry, been swamped the last couple of months with work.

 

 

x2 on the TPS sensor diag. Don't just throw a sensor at it. Verify you have a proper ground, 5V reference signal, and signal output is smooth and linear.

 

I'm not bad working on vehicles, but I need a bit of direction in how to do what your saying.

 

How do I verify the ground? the 5v reference signal? and the signal output?

 

A bit of help/direction would be great.

 

Thanks,

RIchard

[gmtech4]

You need a schematic and electrical experience

 

Alldata.com $30/yr

 

And a real scanner , if you have no scanner , you're done , take it in