Truck stumbles under acceleration

[jkern]

Have a 2011 RAM with 98k miles on it. I change the fuel filter regularly at 12-15k miles, and generally buy fuel from high volume sources. Over the last month or so the truck seems to occasionally not want to accelerate. I have an HS minimax, and when this happens the fuel rail pressure falls to 1-2k psi. if i let off the pedal and allow it to recover for a second or two, then it seems to run well...except if i step into the pedal pretty hard again. I changed the fuel filter and filled up with fresh fuel and after about 250 miles it is doing it again. It seems to be much worse when the truck has less than 1/2 tank of fuel in it. I have read that others have had this problem as well, but most have never followed-up and posted what the problem was. I am guessing a weak fuel pump in the tank or clogged intake. But before i tackle that job and spend the $$$ i was hoping for some experienced input.

 

[jkern]

Oh, and the crank cycle has gotten quite a bit longer as well.