coachmike

'99 dodge ram with 120,000 miles on it. The lift pump and vp44 replaced
under warranty at 65,000, has been trouble free until recently. Seems
to be the same scenario others are experiencing with a little twist. It
will run fine until it "de-rates'" and loses power, but can usually
maintain 55-60 mph. If you let off the throttle momentarily and apply
again, it will usually pick back up. There is no set pattern, it
happens randomly. There are two codes present, unfortunately I don't
have them available with me, but the ecm failed code comes on
immediately after they're cleared, the fuel pump code ( part of it is
p-16 but can't remember) doesn't show until it actually loses power.
However, there are no problems (yet) when the ambient temp is under
80-85 degrees, which leads me to wonder several things:

ecm breaking down electronically due to heat
vp-44 - same scenario
fuel temp too high causing low viscosity / poor lubrication

I should add that I replaced the lift pump, but have no way of checking
pressures. It worked fine for an hour driving to the beach but then
starting it again. At times there is little to no throttle response at
cold startup when ambient temp over 95, as in at the shore. I am
capable of replacing the pump or ECM myself, but don't want to throw
parts at it without more diagnosis.