Crazy increase in MPG, no explanation
2000 ES 1.8L automatic, ~96,000 miles, completely stock.
Chicago suburbs, mixed city/highway (90% suburban roads, 45~50 mph tops with plenty of stoplights and rush hour traffic). I don't drive to maximize my fuel economy, hard acceleration after nearly every light, always passing if I can.
Bought it brand new, I check the mileage at every fill up. Since I bought the car the low was about 22 or 23 MPG. On a road trip (fill it up and drive it empty, ~65 MPH) I would get about 27 MPG, absolute max. On average, about 25 MPG with just shy of 300 miles to a tank.
The last 3 tanks have been 27, 28.9, and just this morning 32.1 MPG (301 miles on the OD and I put in 9.376 gallons). This is with the same mix of driving described above.
I have nearly 5000 miles on this oil, the tires need to be replaced, I still haven't done the timing belt (I know this is bad). I'll check the tire pressure after work, but I know I haven't added air for a long long time.
Does anyone have an explanation? At first I though the OD was counting fast, but my commute this morning was 14.8 miles on the trip computer, which matches google maps exactly.
I'm afraid to change anything and risk going back to my old numbers!