I replaced filters yesterday, no change. Truck was checked out by local dealer and said nothing seemed wrong. But there is definitely something off with it, certain times it just feels dead at takeoff. Even when it feels like it's fueling at the full rate, the truck seems a bit weak to me. Boost gauge will be easy to hook up. I noticed several 1/8" plugs along the side of the block. I was thinking of just t-ing into the fuel line for a pressure gauge. I've also read on here about ecm updates that effect throttle response.....I assume buy fueling at lower boost levels. Ive only grossed 60,000 or less. Can't imagine what it would feel like at 80,000 or more.