Here's one for you all-
For the last year or so I've been trying to figure out why my mileage is down around 25 per gallon city / 29 highway. I put in a TT exhaust 6 months back which may have helped a little but not much. New O2 sensor made no difference. New rotor and Dist cap, plugs, ditto. Summer and winter same mileage, running with AC or without makes a slight difference but not a lot. No vacuum leaks found. I was wondering if perhaps I had a leaky injector and had put this on my to do list when I just took the car on an extended run from central Texas up to Colorado. Lots of highway miles.
As I drove up the mileage began to improve with each tank. Around 30 mpg around Lubbock, 32 at Colorodo Springs. One week of driving around the state, a couple of days in the city and then 4 or 5 in the high country over mountain passes. By the end of the week my mileage on one tank (90 octane - couldn't find higher) was at 37.6 mpg. I wondered if maybe the hard running had made something settle out and my mileage would stay up in the mid 30s highway.
Wrong. As I drove down through New Mexico fuel economy began to fall - first down to 31 mpg, and then across west Texas back down around 29 on the highway.
Does anybody have an explanation for why this is happening? Otherwise the car runs fine, though it seems to prefer the cooler winter weather ('course, I do to, so this may be my imagination). The only constant seems to be lower elevation means poorer mileage. Any thoughts?
TIA, Chris