Last week I filled my 1997 Pontiac Bonneville SE up with gas, and averaged out my fuel consumption. My car is a bone stock 1997 Bonneville SE with a non-supercharged (of course its an SE for goodness sake LOL) 3800 Series II engine. It has a little over 242,900 highway miles, and running superbly. Am I getting the correct average mileage in gas consumption? I average about 25.2 miles to the gallon. My vehicles is usually on the highway or in town alot at speeds from 35mph to 70mph with light acceleration, and trips from 10 miles to 250 miles on any given day. I perform regular maintance on this vehicle.



Oil Changes: 3,000-3,500 mile intervals
Transmission fluid: 25,000 miles
Coolant flush: Once every year
Tune up: At correct intervals

All mechanical/major parts replaced so far:
All 3 Coil Packs: 187,000 miles
Water Pump: 180,000 miles
Fuel Pump: 220,000 miles
Fuel Sending Unit: 220,000 miles
Valve Cover Gaskets: 232,000 miles

Current Odometer reading: 242,910 miles

Not only is the mileage on the mark like JR said..but it'* looking real good too.

I only get about 21.5 in my 98. I was happy with that, dangit....

Boy you must have the cleanes coolent out there.

Not a bad idea considering how much sand and other crap gets in there over that amount of time.
With mixed highway and city driving I usually average around that much as well. I'd be very happy with that kind of MPG with that many miles.

Wow, more then 100k then my 98 and I only get 18-19MPG. Your car looks great for the mileage BTW.

thats about what I get if I do more highway than city driving.
All highway: 30 mpg

That'* impressive MPG. I've been averaging 27 MPG in my 99 with 130K on it. I've replaced the O2 sensor once.

How many O2 sensors have you gone through? The O2 sensor is the likely reason you're doing so well.

My family calls it my "Mee Ma car" or my Fav. The "Grannymobile"

Thank yall, yes she is taken very good care of, although she does have some cosmetic blemishes from all the driving I do, I'm missing the right rear passenger side hubcap, someone stoll my Pontiac emblem off the grill!! GRRRRRR!!!! (Now why the hell would they do something like that) and my headliner is comming down. Or as my little brother puts it "the sky is falling the sky is falling" LOL. She has never been in a wreck, nor had any dents in her. I figure about $300 should get her cosmetically back in shape. I keep the car EXTREMELLY clean, and put it on ramps to pressure wash the undercarraige. She also gets an engine oil flush every 6,000 miles, maybe thats why it has lasted me this long. She was originally purchased with 400 miles on here and has been a DAMN good car. I don't think I'll be trading this one in anytime soon, I'd love to swap my 3800 Series II out for a new 5300 LS4 V8, but I'm sure that would take quite a bit of money to do so. I'm not to big on hotrodding in my car, although I do have to say with that many miles, and my maintainance practaces, she still has quite a bit of get up and go, and still suprises me on the interstate highway. I believe not even two months ago I had the car at 105 mph and she was running at 2,500 rpm'*. I really don't want to push her like that anymore, she'* an old gal, and you don't treat an old lady like that. So I drive her like she is showing her age with that many miles. All in all if I had to replace the engine I'd probably go back with another 3800 non-supercharged engine they seem to hold up better then the supercharged ones I'm told.