2013 Prostar Plus Question - Need your opinion

@Heavyd Hello sir quick update about the fuel pump problem from our conversation earlier on. After we replaced a fuel pump we did a test run with a loaded trailer and a computer hooked up to checking the parameters and everything was perfect for 60 miles how much we test drove it and everything was perfect fuel pump work % didnt go lower that 28 up to 43-45 , my fuel rail psis were outstanding desired and actual ones. After that we assigned driver to that truck and he left on the road , after some 100ish miles truck started to lose power and didnt want to go over 55 mph in 9th gear. We brought the truck back to our shop and checked out that even looking at it you could hear it it was working like on 5 or 4 cylinders aka crap. did the injector auto cutout test and everything is perfect and truck is still running like crap. My concern is when the truck is stone cold when you crank it and until it raises the work temp the truck works beautiful , once it hits the work temp its start doing the same thing : working as crap like 2 cylinders aint doing nothing and does not want to go more that 55 mph in 9th gear even when you manualy put it in 10h gear after less than a mile it will drop it to 9th gear and down to 55 mph. Thanks in advance for youre help and time , it is greatly appreciated.

 

Is the fuel pump still working ok? Is rail fuel pressure and rail fuel pressure desired matching? Need to check boost and exhaust back pressure.

 

@Heavyd Fuel pump still works fine, fuel rail pressure are matching, exhaust back pressure is 0 psi and for boost pressure (if you mean intake manifold pressure) they vary from 27 to 43 desired and actual.

 

That's pretty good. Well, if it runs fine cold, but starts to miss when hot, you might have an injector going out. Are you able to do a cut out test?

 

Hello to buddy if you don't mind. Can you look up this Vehicle number last 6 digits...FN509607 thanks again..