My Dads '99 PSD is acting up something fierce. Starts fine and runs fine but you get down the road after it warms up and its like a switch gets flipped and the truck starts running rough and is sluggish to accelerate unless you go wide open. HPOP is good and putting out adequate oil PSI and Fuel psi is in spec, cyl contribution showed 7&8 lower than the others, we've never done injectors since we've had it so we replaced those two. No change and cylinders still reading the same lower contribution. I know its a fuel issue and for some reason its throwing to much at it at times. Its not a sticky injector cause there is no smoke on start up and idles fine. Havn't been able to get time to get it to act up for me and check EGT at the manifold on each cylinder. It isn't throwing any codes. I'm leaning to IDM acting up. any thoughts on that? I've delt with a bad IDM before but the symptoms were different.