I was on my way to Baton Rouge the other day, and noticed the truck felt like it was dragging something while in O/D. It felt almost as though I was pulling a trailer, and if I kicked cruise off the truck slowed down like I was touching brakes a little, it was very odd. The seems relatively fine around town, albeit a little more sluggish than usual. I've also experienced a 3-4MPG drop, both HWY and city.

I've already done the transmission service with no change in behavior. I was planning on checking the rear end today, but it's raining. My next thought was change the fuel filter (sluggishness?), but to be honest I'm really at a loss as to what could be causing this. Any help would be greatly appreciated.

Truck has 50K miles, all fluids changed regularly, and list of very few mods are in sig.

 

Thats weird. Did you check the plugs?

 

Just pulled 'em, all look ok. I'm gonna put the stock pcm back in tomorrow, but I highly doubt that the tune is the problem, I've had it since march w/out a hiccup.

 

cat could be cloged,are your e brakes could could be rubbing,fuel filter,air filter.

 

I'm with litreddevil. Get your converters checked.