1999 oldsmobile lss supercharged premium or unlead

[Robenstein]

Originally Posted By: Brybo86
Originally Posted By: Merkava_4
Originally Posted By: Mantooth
If my memory serves me correctly, the motor should take 92/93 octane, which was recommended by GM.


What do you do if the gas pump buttons say [87] [89] [91] ?

You might be at high elevation



Here in my town we are at 1,100 feet and 91 is about the best you can get.

 

[Benzadmiral]

Originally Posted By: Silverado12

I traveled through that area this summer, and the regular was 85. I opted for premium and got good mileage. I was driving the 3.5 Challenger, and out west in SD I got 35 mpg. I was stunned it got so good.

My cars got great mileage for their size too. The '86 Mercedes S-Class used to get an overall mpg of 19, with about 60% city driving. That, for a 2-ton car designed in the '70s and built in the '80s, was darn good. I used mid-grade instead of premium, on the advice of the local MB club, and had no issues. When I moved back to Da Swamp and switched to 92-93, the big Benz's appetite increased to 17 mpg.

In part, it might also be that since the air is thinner there, the engine sensors reduced gas consumption to match the air. It also reduced power. You lose about 15-20% of your hp at 5000 feet, I was told.

They space their stoplights out a little farther in Denver than they do here, too, so even city driving in CO was fairly efficient if you didn't get caught in traffic too often.

 

[Trav]

Have a 2000 GTP and its premium only.

 

[user52165]

Originally Posted By: 440Magnum
Originally Posted By: expat
When was Leaded fuel last a requirement for North American made Autos?

Mid 70's?


Unleaded-ready engines started showing up around '71, were prutty much universal by '73, and unleaded was mandatory for the first time (first year of catcons) in 1975.


Poster asked about North American made cars. But - FWIW - my 1979 Accord (Japan) still did not have a cat can and met CA emissions. One of the last if not the last. But only ran on unleaded.

 

[Jarlaxle]

Originally Posted By: expat
When was Leaded fuel last a requirement for North American made Autos?

Mid 70's?


1990.