bonified5

My 95 maxima has over 206000 miles on it and i get about 240 miles to a tank running 87 gas. My engine light is on and i got it checked twice...once it was the knock sensor and another the 02 sensor. Is this effecting my mpg? Also, this guy i know has a 95 max and he says he gets about 350 miles to a tank. any suggestions?

brianw

Definitely yes.

o2 sensors can and do go bad as they gradually degrade- I'd replace all three of those first and see what happens. FWIW 240 miles is definitely on the low side, although in Los Angeles traffic in a purely city traffic commute I've seen as low as 260 miles/tank in a 4th gen...

(that said the exact same car did 425 miles on I-5 at a constant 80-85mph, your specific driving conditions definitely matter)

bonified5

k thanks and I drive on highway about 10 miles to and from school with some traffic lights and i am on a good bit of back roads also. Lately I havent been accelerating hard. I want to get the tranny flushed, how hard is it to do? Its an auto.

brianw

That's barely enough time for the car to warm up, so terrible fuel economy wouldn't surprise me. You can do a drain/fill and get about half the fluid or 1/3rd out of an automatic, but without a power flusher that for the most part only a shop will have, you can't do a complete flush.

bonified5

ok and I do let the car warm up in the garage for about 10 minutes before I go. Also, would it be better using 91 fuel?

brianw

Yes, it would be better with 91 fuel... but not THAT much better. Swap the o2 sensors and spark plugs first and get back to us.