Earlier today I nearly broke my trip record. The weather was in the low 80's, rather humid, and clear. Driving home from work I averaged almost 130mpg with approximately zero net elevation change, up until I turned into the dirt road going up the hill I live on. I was able to maintain around 120mpg on level terrain between 38 and 48mph, and broke 130 average after EoC up to the foot of the hill. Sadly, when I pulled into the garage, I was 2.8mpg short of my 220% EPA goal.
I can't think of anything that might have made today different than yesterday. Most days I'm at about 95-105mpg at 48-55mph.
My tanks aren't really reflecting these high trips due to occasional lending of the car to my father-in-law. Apparently a 100 mile trip at 50mpg can "ruin" the rest of the tank. :P
You might notice a very conspicuous CEL on my dash. Funny story, that.
Before I left Florida, I loaned Gaptooth to my father-in-law. He put nearly 500 miles on it, and when he brought it back, he said the car had been "running a little rough". A quick glance at the FCD revealed he had averaged about 33mpg, and it was vibrating like a jackhammer. Apparently one of the spark plug wires had come loose shortly after he left, and he had been running on two cylinders and dumping 1/3 of the fuel out through the exhaust pipe. The code read something along the lines of, "Catalytic converter performing below threshold". I was hoping driving it would clean up the cat, and at first thought it worked (went nearly a thousand miles before the light came on again), but the CEL has been coming on more and more frequently. It doesn't affect MPG or performance and I can slip past inspection by clearing codes before going in, but the yellow light bothers me so I'm probably going to get a replacement soon.