I drive a 1997 Lexus LS400. My family has owned the car since 1997 and it still runs well. I am having a problem with the amount of gas that person with the distance i drive. I fill the tank of my car up with about 65 dollars. ive read on the internet from previous owners that the Lexus has about a 19 street and 25 HWY gas usage. the car has a 22 gallon tank. I should be getting about 450 to 550 miles with a full tank i believe but now my car only goes about 280 miles before i have to fill the car up again. Can someone help me with an answer or give me advice on how to burn less gas or let me know if there could be a problem with the car itself. the car has about 265 hp and it runs on a V8 engine. it takes premium gas but ever since gas prices went up i started putting in 87.

The octane that you're using could definately have some effect on it, especially if your owners manual tells you to use higher octane. Also, with a car that is 10+ years old, there's probably considerable engine gunk buildup. You can get a little bottle of gunk remover (I think it's called gas out or something like that) at your local auto zone/auto parts store. Good luck!

You changed gas...pure and simple. When you switched to 87 the cars knock sensor went off and retarded the timing. Now you car uses more fuel, has worse performance and is going to cost you more in the long run. And check your air filter, like the other guys said....#1 issue related to lose of gas mileage.

One of the biggest culprits of gas mileage problems is the air filter. A dirty air filter can really rob your car of mileage. Also has the car been tuned lately with new plugs and wires? The engine in the vehicle will also have to work harder and less effeciently to produce expected performance with 87 octane gas.

perhaps its time for a full tuneup..using a lower octane fuel can decrease your spark plugs life..

It is because you went from a longer burning fuel that is used for long crank engines to a short burn fuel made for shorter burn cycles. the best thing to do is keep up on your maintenance and your 4 wheel alignment is perfect( any kind of drag will slow you down and waste fuel