PontiacBonnevilleClub.com

OK, WTH? I picked up my new/old '97 Anniversary Model Bville last Sunday (I'm freaking out the neighbors-My '99 is white too and the cars are nearly identical) and yesterday I had a 200-mile trip here in the Bay Area.

Filled up right to the top before I left, and 206 miles later did so upon my return. Nice day, not much traffic, mostly freeway using the cruise control. Car took 6.76 gallons upon my return, which works out to 30.47 mpg!?

My '99, which I bought new, has never gotten better than 25 with the same type of driving.

What mileage are youse guys getting in similar driving? This is certainly a pleasant surprise. I'm beginning to think I scored big-time with this purchase.

Dunno what is normal but that sounds pretty good to me!!! I wouldnt complain. LOL

my car varies so much, I have yet to take it on a trip since I fixed some issues, but used to before the issues started I could regularly get 28ish on strict hwy trips, my personal best is 34 mpg that I got in about 150 miles of straight interstate driving

DCJREDLINE wrote:Dunno what is normal but that sounds pretty good to me!!! I wouldnt complain. LOL

I'm not complaining.

I'm astonished.

Let's find out what plugs are in there and remember it for your 99.

Both of my Bonnevilles do better, but the 95 isn't by much. And my comparisons are 100% highway, not mixed like yours (from Oregon to the Bay Area).
Your 99 will do better in the City than either of mine though.

The 97 I had got as high as 35mpg on the interstate running at 75mph.
The 02 I have now hasn't gotten that good.

I wouldn't doubt your SSE has 3.05 gears, and your SLE has 2.86 gears. That alone would make a huge difference. I don't know the RPO codes to be able to confirm it though.

My old Bonneville would get 30-32 MPG anytime on the highway.

Its always amazes me how much a good tune-up gives a car. My g/f purchased a 05 Grand Prix (base model) a few months ago. The car had like 74000 miles on it when she purchased it, and would get right around like 24 mpg with her mixed driving. I gave the car a tune-up with new plugs, wires, O2 sensor, air filter, inflated the tires up to 35 PSI (from about 30) and now shes getting right around 27 MPG under identical driving....

When was the last time you tuned up the 99?

I rarely if ever have gotten more than 20mpg in mixed city/hwy driving.

Eric, he's got bigger problems on the 99, lol.

Even as I say that, my buddy has an 05 SLE and he regularly gets 30+ MPG with it, mostly rural 2-lane driving.

The 96-97's had the best MPG ratings of all Bonnevilles produced.... NA for sure... the 96-97 NA 3800 was rated for 19 City and 30 Hwy...

My 95 was rated for 19 City and 29 Hwy... It easily did 30+

Believable. I used to average 30+ mpg in my old Buick during the summers. Mostly 2-lane rural highway driving helped there. Best I ever saw was 39 mpg, with a very sore butt from all the sitting it took to get that. More often I'd get 33-35 mpg on all-highway trips.

My 98 is getting ~28 on average mostly highway and is stock for the most part I believe it still has the original O2 sensor I should replace that.

Phantom, my rule of thumb is that if you know your sensor is 50k miles or older, or you don't know how old, replace it. The fuel savings quickly pay for it. AC Delco is the safe bet. Never Bosch.

AC Delco, Delphi or Denso. No Bosch.

Bob Dillon wrote:OK, WTH? I picked up my new/old '97 Anniversary Model Bville last Sunday (I'm freaking out the neighbors-My '99 is white too and the cars are nearly identical) and yesterday I had a 200-mile trip here in the Bay Area.

Filled up right to the top before I left, and 206 miles later did so upon my return. Nice day, not much traffic, mostly freeway using the cruise control. Car took 6.76 gallons upon my return, which works out to 30.47 mpg!?

My '99, which I bought new, has never gotten better than 25 with the same type of driving.

What mileage are youse guys getting in similar driving? This is certainly a pleasant surprise. I'm beginning to think I scored big-time with this purchase.

Our ole '92 has never gotten better that 28.8mpg on the freeway. I have a friend in MI that has a '99 Buick LeSabre. He gets 30+mpg on a regular basis. - BC

My 94 SE gets 15-17 MPG on Chevron 91. Mostly due to a heavy right foot, and driving 30 miles from 3800 ft elevation to 1000 ft and back again every day, on twisty mountain roads! She might see 20-22 on the freeway, but I will never know.

Be happy with your good MPG, and know that some folks here are extremely jealous!

Running a 94 SE (non-sc) on premium will hurt you more than help in the mileage department.

so i would assume that something is in need of changing when my car uses a little under a quarter of a tank to go 52 (is round trip from my house to work and back) miles all highway in my 96 Bonneville SE?