^enlightening IS_250...da-bizket great point and now I'm really going to see how many miles I get I hope my 17.2 doesn't mean 15...

 

...my driving habits are close to sc's and my computer readout says that I'm getting 21.2....but by my calculation I'm around 19-19.5...but I'm not complaining,since it's more city than hwy ed

 

05 with new spark plugs + New MAF + new Air filter + new Denso oxgyne sensors + new fule filter, driving 70% city * 30% high way + PWR always on + foot alway to the floor on the padel. I get usually 19 MPG and some times little better but not more than 21 MPG.
old way calculation 17 MPG

 

90% of my driving is stop and go city driving.

Most ever driven on freeway without having to stop is 36 miles.

Gasoline used has always been 91 (the highest sold in my area).

PWR setting is always active.

AC/Heating always on and set to 70 auto throughout the year.

Never peal from a stopped position.

Average MPG since first fill-up is 15 MPG.

 

I have a 2002 with 43000 miles, K&N air filter, burn 89 octane 10% ethonal. I get 21.? mixed driving and better highway. I have heard some people get bad mileage during the winter, but not on an SC. Tire pressure? Bad MAF sensor? Clean throttle body?

 

My '02 gets about 20 to 21 mpg with a mix of city and highway, somewhat dependent on the a/c use. Running with PWR active doesn't seem to make any real difference. (I have just under 70kmi on it.) I run regular gas in mine and have seen no issues for the 35+ kmi that I've owned it. I attempt to keep my tires around 31-33 psi. I think that I installed a K&N air filter last time. I've never changed the spark plugs. There are times when it has gone as low as 19 mpg, mainly when I got a bit overaggresive though. I also use either standard oil or a synthetic blend (from Firestone).

Running pure highway miles, I've seen as high as 25 or 26 mpg

Regarding the display, yes it is off, at least on mine. The display typically is about 1 mpg higher than reality (1 +/- 0.5 mpg).

 

One actually needs to add gas, do mileage check when adding gas again, and do that 4 or 5 times without a break between. Use the difference between the amounts of gas put in the car along with the miles...In other words five gallons and 100 miles, 8 gallons and 150 miles, and so on until you can have a real average...Doing that I get around 17 mpg to 19 mpg in in the city, and as high as 23-24 doing pure interstate driving at 55 mph.

At 70 to 80 mph, it drops to about 18 mpg (as near as I can figure)

My suspicion is the reason the computer is off, because it does not count idle time (or does not count it accurately). I had a Ford truck that would give consistent mileage on the computer when I was out on the highway, but when the wheels were not turning, it was clearly not counting the gas being used (I had bad gas, thank you Exxon, and ran about the last four gallons out with various times of idling and racing the engine to keep oil in the cyclinders, but the barely moved except a couple of trips around the block to keep oil in the cyclinders. The computer I reset at the begining, and it showed 16 mpg at the end!!!)

I tried doing the "fill it and go and check miles for a one time event", but that is inaccurate way to measure, even using the numbers of gallons as it tends to be different amounts of gas and the gas pump may be off, and cheating you.

The worse problem for both the car computer mileage measurements and any other manual system, is the idle time where the car sits and burns gas as well as evaporation issues.

 

They make a good point. Calculate manually instead of reading the computor. I will do that on my next to test my cmp. Anyway when I was driving solo 75 % freeway 65mph I got 23.1 (according to cmp) When I was solo 50/50 dropped to 21.7. Now I drive my wife also to work few miles from mine and get 20.00.

No she's not that heavy.