I finally got to borrow my wife's CVT Premium, PZEV hatch for a long freeway drive to a hike over the weekend. Our car has been notorious for bad mileage, BUT a recent visit to the dealer and insisting on a diagnostic seemed to MAYBE do a step function improvement in gas mileage, even though they claimed they didn't do anything to it. I did roll over the 1000 mile mark during this drive.
I zeroed the mpg average gauge and started out in approx 40degF morning temp, pulling out of a warm garage. Blue light went out soon after pulling out of the driveway.(verified average guage is 1.2 miles optimistic based on manual calcs on this same tank)
First 5 miles was 14-16mpg, with the efficiency gauge pegged over on the plus side (max fuel usage) even when coasting downhill, on sections that the injectors SHOULD be shut and are normally pegged the other way when the car is VERY warmed up.
The rest of the day is spent making up for that first 5 miles and probably explains why people with LONG commutes are happier than people with shorter commutes or errand runners, with this car.
I proceeded to drive the entire drive VERY carefully, even drafting cars and trucks, keeping to 64mph max and no sudden accelerations. Coasting up to stop signs from WAY back. Only about a mile from my house to the freeway. Very little non-freeway driving on this trip.
At about 8 miles I finally broke 20mpg per gauge.
At about 20 miles I was edging up above 25mpg.
At about 40 miles of freeway, the car was making up for the crappy starting mileage and a very tiny bit of "city" and getting over 30mpg.
At about 60 miles when turning off the freeway the car was doing about 33-34 mpg, dropping slightly for some 35 & 50 mph easy country roads.
After a couple hours cool down and with temps in the 50's, I did get up to 35+ mpg for the average on the way home, maybe dropping to 34 with a few 70mph stretches, but hanging at 35.1mpg as I exited the freeway. Driving the stop-go last single mile to my suburban home dropped it a suprising amount, down to almost 33.
A GREAT car for long freeway road trips and long long commutes. Its has its challenges making up for that first 5 miles "warmup" though.
It does look like the computer "diagnostic" hookup, did something to the car, IMPROVING overall gas mileage. Still not exactly kicking up my heels about its ACTUAL "City" mileage, but at least I can see some hope now of the ever increasing time they are asking for mileage break-in, and "summer gas" getting us into reasonable "mixed" mileage and awesome Freeway mileage.