Originally Posted by TheNoachSHO
So I got a new job and am driving my 05 Hemi around much more than ever before. Little background, bought it 5 years ago with 56k on it and only now have 80k. Never drove it more than 50 miles from home and used it to mostly tow my smallish boat.
I've always got about 13 MPG and maybe i'd see 15 a few times if I was really lucky (not towing of course).
so I took it on it's first long trip and had something funny happen. About halfway into a two hour ride I was getting about 14.7 to 15MPG's. Then I felt a slight stutter and my MPG's shot up to 16.5 - 16.8. On my way home I got 14.2 for most of the trip then suddenly about 3/4 of the way back it shot up again, only this time I actually saw 17 MPG!!!
Clearly something is going on. I've always used Mobil 1, 5-20 and a Mopar filter every 5k. I'm thinking that maybe the MDS solenoid was gunked up and finally free'd???
Does anyone know how the EVIC calculates MPG's? Has anyone experienced this before or have theroies about it. I'm just trying to figure out what the cause was so I can learn how to drive it at maximum MPG.
It could be a good guess that the MDS is misbehaving--it should be almost undetectable when it switches from 8 to 4 and back.
I dunno if a Seafoam flush followed by a new refill of Mobil1 would help degunk it--I wouldn't try it until someone with your same year engine chimes in.
As for how to get the max mileage from the Hemi.... forget it is a Hemi until you really need or want a Hemi. As in, pretend there is a bottle of nitroglycerin between your foot and the gas pedal. Keeping a steady speed as opposed to moving speed up and down and up and down helps. Easing off just a small bit on uphills can help, depending on the hill.
Oddly enough, taking it too easy from a stop can hurt, as the quicker you can get up into the higher gears the better your mileage will be UNLESS in the process of getting there you hit the gas so hard that it enriches the fuel mix. Somewhere just a bit between half and 3/4 throttle tends to work best for most engines.
'Course the real method is to get a 14 or newer with the 8 speed that can put you in the low 20's at cruise--but even those suck gas in slow traffic. Thats why diesels exist.