Unusual low gas mileage

orrc · Post by **orrc** » November 30th, 2007, 7:18 pm

ya my mx3 has been running great since i got it but lately it is having gas problems. I just filled it up a couple of days ago and it only had 160km on it since I last filled it up and the gas gauge said i had less than a quarter tank left. Any idea on what might be wrong?

Tunes67 · Post by **Tunes67** » November 30th, 2007, 7:45 pm

Hard to judge how much gas you have lost there from the information you have given. Do you have a locking gas cap? Cause if you have lost as much gas as your brief post makes it sound.. either you have a bad leak or someone is siphoning gas from you.

Tunes67

umcamara · Post by **umcamara** » December 2nd, 2007, 2:11 am

It's winter, that may not be that abnormal. Do you let your car warm up for awhile, do you spin the tires on ice, do you have a low-temperature thermostat? When was the last time you did a tune-up? Changed to winter oil?

Details...

umcamara · Post by **umcamara** » December 2nd, 2007, 2:13 am

Did you remember to put winter air in your tires?

SuperK · Post by **SuperK** » December 2nd, 2007, 2:06 pm

do you fill up with "Cold weather" fuel when at the gas station?

do you put mittens on your intake manifold?

The gas gauge is very inaccurate, in my opinion. See what your final mileage says and if it's abnormal, run yourself a basic comprehensive tune up.

It might be worth running some of that injector cleaner to see if that does anything for you. The only other issue I would see is to throw in a new O2 sensor, maybe get a diagnostic to see if you're running unusually rich.

Otherwise, take it easy on the road.

umcamara · Post by **umcamara** » December 2nd, 2007, 2:23 pm

Yup. You'll usually get almost 100 km's or so out of it after you hit empty.

neutral · Post by **neutral** » December 8th, 2007, 10:34 am

If O2 sensor hasn't been replaced within 100K, a sensor gone bad can hose your mileage - leaving the engine ECU constantly "guessing" at fuel mix balance.