We have a 2011 e450 that we just got. Like you I found it to be less than desirable for climbing hills or anything. Ordered a 5 star tune and put it in this past weekend. The short drive I took sure seemed to be better. Throttle was more responsive vs before and it cruised just a little better.
We leave next week for a trip so will know later. I think an improved air filter will help some, but to get the best out of it you will need to get rid of the oem muffler so it breathes out better. I use Gibson products and on my old F250 they recommended teaming the muffler up with a K&N. Did seem to help, so finally made a FIPK up for it and it did run better, but I also had replaced the ign with the red kit msk (I think, cant remember) and yes it would haul. Dont know how they work on an obd 2 system.
