i need some help with my truck,it seems very lazy,i sent to the local mack shop for alow power check and fuel pressure check and fault test,they came back to me ,and said i have boost leaks every where,my fuel pressur was fine(they wouldnt tell him how much!!),and one injector fault,that said no 6 injector inactive,they said not to worry about this??? so ive come home put all new inlet hoses and clamps,torbo clamps,i pressured tested in,all is fine ,no leaks,took it down the road,no diffrent still seems lazy it makes 2ookpa manifold pressure ,(27-30 lbs),i pull three trailers up north of western australia,all up weigh about 70-80 tons,even with one trailer with 19 ton on it struggles to a point where other trucks with more weight pass me,any help would be great