I have noticed a lag in acceleration after the truck shifts out of first. If you really step on it it takes off, but even going only 25 mph or so you really have to press the pedal down far to accelerate quickly. I have tried several tanks of premium fuel to see if there is a change, and I haven't noticed anything. A few times the truck has also stalled at idle, most recently when I stopped to shift into reverse. I have read in other posts about the spark plugs needing to be changed, but mine were changed only 3000 miles ago.

Any thoughts?