ICE mpg dropping

[J-Max]

Past few weeks I've noticed, though my overall mpg ranges from 43-45 the instant readout (ICE) is way low where previously it was much higher. Like cruising at a steady on level roads at 40-45mph it will barely hit 30 where in the past it would easily be over 40 sometimes WELL over that. To get it up to 30 now I really have to feather the throttle and keep the power output just barely over where the EV mode would take over. My trip summery is barely over 45 after it's been warmed up (like return trip home after sitting a few minutes to an hour or so) where as previously similar trips could be mid 50s to upper 60s. 

 

That said, in EV mode everything seems exactly the same, for example how long I can run in EV mode, how far I can accelerate from a stop, how quick the battery drains and recharges etc. Also, coming home from one direction, there is a slight downgrade almost a half mile before I have to turn onto my road, I always get to 40mph at the peak and let her coast in gear as long as possible to regen the battery as much as possible, I am still only dropping to 30-32 mph at the same exact point before I have to brake for the turn. THUS... no apparent added drag like a sticky brake, low tire psi (all 4 tires consistently 48psi).  I did have to replace the front left wheel bearing several weeks ago, at the time I had already noticed lower overall mpg, as mentioned above it's been 43-45 before and after the bearing change. When I noticed the bearing noise I drove 'gently' until I could change it, and after the change continued to drive that way to see how much higher the mpg would go, last year, driving the same style I could get 50+mpg per tank (got just over the magic 600 mile per tank). When it didn't go up I started paying closer attention to the readouts, this is when I noticed the ICE instant readout was much lower then before.

 

 Besides checking for any increased drag (see above) I regularly(once a month to 6 weeks) pour a bottle of Techron in the tank. A year and a half ago at 90k I had a dead injector, wound up replacing all of them as well as the coils and plugs. At the time I checked the air filter, though the original FoMoCo filter, it looked good saw some light thru it and no build up between the pleats. Anyhow, since the lower mpg doesn't seem to be from any new rolling resistance I figure it's something with either the engine or computer. Power from the engine seems to be the same, no noticeable increase in how much I have to push on the throttle to accelerate the same ways as before, no CEL, idle feels the same, etc. Figure maybe with 104k on the clock the air filter could be a bit restricted so I replaced it a few days ago and dumped in a large bottle (treats 20 gallons) of Techron again. Also got some MAF cleaner and sprayed that down real good...all that made no difference.

In the pics, I was at a steady speed on level roads, I never really paid close attention before but did enough to know at the two lower speeds the instant shoulda been over 40 and the one over 40 with the cruise on at the same speed +/- on that same stretch of interstate it was usually right on 40.

Any ideas?  TIA.

[J-Max]

Just to break up the sounds of crickets chirping.....

I ordered a new MAF sensor, which also has the AIT sensor built in. I'm guessing since it still runs normal, maybe the AIT is faulty and telling the PCM it's 20° below zero (IIRC that is the default if the temp sensor goes TU) and it's just running very rich.

[homestead]

Mine has gone down in mpg's too but I suspect it because the weather is warmer and the A/C is eating up some of mpg's.

Does the best in spring and fall when neither the A/C or heater are running.