mpg's

[superdukie]

i have a 2005 f350 6.0 when i bought it used i was getting 14.9 mpg at the worst i have turbo back straight exhaust and air raid intake when i put a triple dog tunner on it i was getting 18mpg easy about 6 months ago i got a load of really nasty fuel i was changing fuel filters once a week but the damage was done. it started blowing blueish white smoke hard cold starts surging when going up a simple grade and horrible fuel milage iv since replaced fuel pump,filters,injectors,and batteries most of the issues are gone i get a little smoke during start up and goes away and im only getting 11 mpg with sct tuner with mpd custom tunes ive gotten rid of the triple dog is there anything else i can do or check i was planning on rebuilding fuel presure regulator next week it seems to have good power any help would be appreciated

[dannyboy950]

You may be at the point where the only cure is injector replacement.

If the fuel has sufficent amount of particles small enough to pass thru the filters and screens it will act like blasting sand and enlarge the nozzle beyond specs allowing too much fuel to be injected, this eventually affects the combustion ratio causeing poor fuel economy. If left unchecked it can reach a point causeing cylinder/ring damage even to the point of cylinder hydrolock.