Hydraboost unit and fuel economy
I just want to let everyone know this. I have an 08 F250 6.4L Crew cab short bed. I have always complained about the fuel economy since day 1. It actally got worse at 40,000 miles, down to 10.5 mpg arount town and 15.5 mpg hwy. I put an edge tuner and cat back delete pipe on. I saw about a 2.5 mpg increase but still never averaged better than 18 mpg on hwy at 65 mph. I did see one time 20 mpg at 60 mph for a 1 hour flat terrain drive. Here is the good part.
Recently, at 52,000.00, my hydraboost unit failed and my brakes were metal to metal on drivers side front. I had a brake job done and was told all 4 rotors needed to be replaced (odd I thought). After getting my truck back I noticed it drove much nicer, smoother but with a little, ever so slight dead spot on the brake pedal, solid brakes tho! I took the truck on the hwy and reset the mpg meter and was astounded to see 28 mpg! Yes on the same stretch of road where at best i saw 20. Long story short. The hydraboost unit was always appling brake pressure, hence poor mileage, always feeling as tho i was towing something, and the slight dead spot in the pedal is normal.
Hope this helps someone! Truck drives great now and mileage is 16mpg around town.