On the 2003 Mack with a 350hp E7 and allison auto tranny that we just purchased a few days ago, i noticed driving it home that when pulling hills, then sometimes when you put the pedal down to pull the hill then the turbo spools up but then sometimes after 5 seconds or so then it will spool up even more and it has quite a bit more pulling power even though the tach doesn't move. It does it with the cruise on and also with it off so i don't see how it could be the pedal sensor. Could this be what they call a dual HP engine? Why would it be doing this? It didn't do it on every hill, sometimes it had the extra power immediately but other times it was delayed.
I owned a 2003 CX 613 with a E7 425 and a 10 speed. The engine was bullet proof , but pulling it would hesitate then I would feel some extra kick. I replaced the throttle position sensor. That helped quite a bit. I don't know if there is a way to test that. I do not know any thing about your automatic. I would be interested to see some replies. Good Luck!
Is it a 330/355 or a 355/380 maybe. Go to Rochester diesel and get a blixxton. Then if your still not happy they have injectors and a bigger turbo. Check for boost leaks 1st and take the charge air piping off and check the impeller shafts for damage and play Tuning & Modules | Diesel Injectors | Turbos | Nozzle Honing
