hi guys, Ive been noticing slightly worse than expected gas mileage out of my '99 LS. Its only got 83,000Km or 55K miles or so, and I'm getting roughly 450 km/tank on the highway. There are no codes, and the engine seems strong. I just bought it, and it absolutley flew through its etest 0 readings on some. could it still be the O2 at that low of mileage? or might it need some tune up items? Thanks,

Ryan

 

Put in a turbonator.
-Rik

 

tune it up first, and see if you get any changes, and change your fuel filter and then tackle the o2 if mileage doesnt get any better

 

Yeah I'll start cheap and go from there. I put in new plugs, but I may need to go deeper. LOL turbonator. Those are the best.

 

plugs are just scratching the surface! but its a start. good luck!

 

i have a worse problem than you actually. I get only about 20mpg on a stock motor with 130k. wondering if it's the o2 sensor that makes it run like crap.