I agree, it seems that every time I get a new flash upgrade my mileage goes down. On my 2015, in 10,000 km I was averaging better than 10.5 liters per 100km.Went on a 1500 mile trip, mpg down 2mpg to 25.Around town 14.
Think largest cause is flash changes shift points mostly in 5th or 6th around town stop and go.
Anyone else see the's changes?
Aftermarket tuning could fix your shift points, but you run the risk of voiding a warranty..I have waited to post on the oil flash results until I had a consistent mileage history, well I think I have sufficient history with me and my wife driving. My average has settled out at 22mpg. My observation is, considering new tires, colder weather, we both have noticed that the shift points have been consistently 500 to 600 rpm higher than before, 3K vs. 2.5K. Transmission holds 6th and 7th for what seems like forever. Yes on the County back roads in OK with 50 mph speed limits I hate that it now holds 7th gear, I have to pull out of the throttle to get transmission to upshift and then gently roll back into throttle to hold 50mph. It also holds 7th up to 65mph on Expressway traffic, same tactic to get 8th to shift. Never had an issue before flash. Still happy with 22mpg average vs. my friends 2014 GMC averages 16mpg.
Actually I did and with mixed results. The DIC shows a request for 8th while still in 7th for about 30 seconds before an actual up-shift, but if any additional pressure is applied to throttle, transmission down-shifts to 7th. So little help. According to GDE their tune does not affect the TCM (Transmission Control Module) just the ECM (Engine Control Module).Gearhead, I have not done this very often, always forget about except when towing, but have you tried manually shifting from 7th to 8th, or the next higher shift point you want instead of waiting to shift, especially on flat lands. Like I said have not done it very much, except towing, so not sure, just a thought.