i cant think of the other things my car does, but one i know of, i think my odometer exagerates on mileage. i did a trip set from my house to my girl friends house and it says 23.3 miles. and then i went on map quest and typed in my address and her address, and it says it is a 12.7 mile trip. and it shows the exact directions i take every day to my g/f's house. so wtf.....

its not you mine says the same thing, I thinkk yahoo and mapquest measures in a stright line but we take turns and such. On top on that i think 15 and 16 give slightly different odometer reading. Maby not speed reading is affected too much but defiantely the odometer reading

i dunno dude i always thought the alero measured its mileage a little fast. i mean it shows i add almost 600 miles a week, when it feels liek i drive 20 miles a day....

hell it even says i add 60-100 miles a day....when all i do is go to school and my g/f's house which is on the way...

have aftermarket rims? Wrong sizes not only throw off you speedo but your odometer also.

do you think bigger rims would throw it off that much? i mean that seems a lil extreme.......

well i have 17's and it came with 15's but if i remember coreectly the tire size was 19? or 20? i forget, but anyways, i have 17's and i had a choice between 2 different tire sizes, a taller size, or the smaller sidewall, which is the exact same height as my stock tires height so if anything im affected my 1 mph.....or 2 max....

It all depends on that sidewall.

With 17's on an Alero they should be 45. Anything different with cause that problem. But it sounds like the sidewall is too small/short

dunno but i just remembered another wierd thing with my car. i have a 60 series slowmaster muffler. and i have a faze air fuel gauge, and i have noticed when ever im driving 65+ mph, and let off the gas, the exhaust hums like im giving it gas but the rpms drop to around 1,500 and when i look at my A/F gauge it shows i have exactly no A/F ratio what so ever. there is no light, and the exhaust is humming, and the car slows down rather fast untill it reaches about 55 mph, then the crazy A/F ratio returns and it coasts like normal. and while this is happening, i can give it gas at anytime and my A/F ratio returns, but only if i give it gas during this interval. i am not if this is a back pressure issue or something, but i have heard words like; "exhaust brakes/breaks" and "burnt exhaust valves"

actually, larger rims would make the mileage appear less than what you actually drove. You get more distance per turning of the wheel... so hence you go further and register less mileage with larger tires.

^^ good to know, but we all know the bigger the rim, and the heavier the rim, so you might go more miles but you wont go more miles to the gallon :rolleyes:

anyone wanna tell me why my A/F does this?

my mileage goes up faster than i thought it would too, it just doesn't seem like i drive THAT much. next weekend im going to my gf's school in wisconsin, ill do a trip odometer on that. then have her do it when she comes back...i doesn't seem like i drive THAT much either

^^ no poop!, skyler said, you should watch the mile markers on the freeways and highways, and see if they are as accurate as your odemeter. i havent tryed this yet.