First off, let me apologize since this will be a bit of a repeat, but I'm going to do it anyway.

I now have approx. 44K miles on my DMax, and over the last month I've noticed a fairly gradual loss in power, followed by a drop in fuel economy down to around 12-13mpg driving down the highway between 65-70mph, and about the same around town. Most days when you step on the throttle, it will gradually pick up till the tac hits around 2200rmp before you feel the power kick in. Went to make a left turn the other day and about got t-boned cause the darn thing wouldn't go. As long as the rpm's are up, no problems. Hence forth I'm driving around with my foot on the floor most days.

I've read quite a bit about injector problems, and am not quite sure if this applies or not. It doesn't seem to smoking at all, can't tell if there's fuel in the oil, but have occasionally noticed a raw diesel fuel smell.

Fuel filter has been replaced, oils changed, everything I could think of to do.

Took it to the dealer, he's keeping it overnight. They claim they are looking for a specific code and to run more diagnostics, but at this point it looks like I'll get to pay the diagnostic fee and get the truck back no better off. Is there anything else I should be looking for, or asking the dealer to check???

At this point it's the pits to drive, and costing me an arm and a leg, so any ideas would be helpful......:(

have check the sensor on the fuel(gas) paddle.....i have clean mine several time,i had dust and dirt build up...

might be a mass air flow sensor clogged or out

if injectors it will cost you NOTHING. you do not say where you live but maybe if you do someone will tell you a good dealer to go to who wants to fix your truck instead of rob your wallet.

I live in Elko, Nevada. 120+ miles to the next nearest Chevy Dealer, and another 120+ miles to the next one after that. I took a quick look at the MAF sensor, but didn't touch it since I didn't have anything to try to attempt cleaning it (looked fairly clean, but looks can be decieving, right). If the dealer is looking for a code, he's going to be there for a while since it's not throwing codes. I also assume asking for a copy of the tech's notes stating flow return rates, fuel rail pressures, etc would result in a good laugh until they realized I was serious. I guess I don't mind paying the diagnostic fee, at least it gets the problem recorded in the system (which then if something happens in the next year pertaining to this issue that has to be covered under warranty, I can petition GM to reimburse the Diagnostic fee). It's just going to be interesting on the checkbook paying for fuel. Maybe I'm being too pessimistic and they'll find something wrong. I'll keep everyone posted... Thanks for the info.

Has the fuel filter or the air filter ever been changed? A gradual loss is sometimes caused by a lack of maintenence with those items. I would have gone there first.

Air filter has been changed every oil change (around every 5000 miles). Fuel filter changed every 15000 miles (per the manual), although now I see the need to consider changing it more frequently. I did go ahead and change the fuel filter again right after I started having problems thinking maybe I got some bad fuel, with no effect...... Haven't heard from the dealer yet today, so well see. Thanks.