Well, i simply do not know

ok. i installed my door sills and had to disconnect 12 volt battery to do so which reset everything in the car including (actually saved addresses and phone settings were ok) my trip meter.

now before i was at 64 mpg. after install, everything was reset except odometer. well drove around a little, did about 15 miles at 58 mpg then refilled.

according to estimated gas use which should have been just over 7 gallons, well i put in 8.335 gallons which puts me at just under 54 mpg. that is nearly a 10 mpg difference.

what happened??

this is only the 3rd time putting gas in and the previous two times were within 2 mpg high once, low once.

got gas at Costco, so sent them an email with my concerns. will post their response, but not sure its them. any thoughts on this? is it possible the odometer is messed up? seems unlikely

**edit**

ok, its been a while, but have finished the next tank and its low as well...622.9 miles MFD says 68.1 which should mean it would take 9.15 gals... well it took 9.983 which computes to 62.4 mpg. with 70,000 miles of Pri driving, i have never had any single tank as far off as this one and this one is still MUCH better than the previous one.

i ran this tank in eco mode the entire time (after playing with it this afternoon, i figured that after about 3 inches of pedal travel, its actually in power mode anyway. its almost like the old 4 barrel carb days when it switches over)

but wondering if maybe i try running it in normal mode to see if that makes a difference

 

hmm, well not quiet that bad, but IF...IF say i was to have shown off the sills SEVERAL times which would mean the doors were open an inordinately longer time than normal which would have run down the 12 volt battery which means on startup the engine would have to run longer to run the motor to charge the...

hmmm and to think it all started with a fly

anyway, i am thinking the pump ripped me off or i was siphoned. i do live directly across the street from a park where tons of kids hang out. now, i have not noticed any damage to my car or anything that would indicate a break-in.

other than waiting to see if Costco finds anything wrong with the pump, the only thing i can do is just wait a few weeks until i can get a decent fillup and try it again...

 

well. only 50 miles on new tank... now IT SAYS 62.2 mpg... i guess we shall see.

 

well currently we basically have an extra vehicle so the 2010 does not get driven daily. i still use the Zenn to commute to work and for short errands simply because even great mileage on the 2010 cant compete cost-wise with the Zenn.

 

well this is my 3rd fill. including a "half fill" but that was the dealer tank. filled that with 6 bars left because i was headed out on a long trip and plus, wanted to move out the dealer mileage. i was out of town when my car was delivered and i told them when they called i was unsure of my plans (up until they had called, i had not even looked at the financing options) which, i think, gave them the impression that i was not going to buy it. well when i did finally pick it up 4 days later, it had 25 miles on it at 35 mpg. well, i brought it up eventually, but the point is, the first mini-fill and the 2nd fill were within "normal" ranges. less than 3 mpg difference. one higher, the 2nd lower...

just going to see how the next tank works out. Costco responded to me that they forwarded my concerns to the station involved. i dont expect to hear much from them anytime soon... so we shall see. sitting at 300 miles on this tank, so still a ways to go.

 

new tank info, OP edited

 

2-3 mpg i could accept but 5.7 mpg on this tank, 9.7 mpg on the last one. what gives?