Lexus fuel economy question?

Actually your car has an L6 engine, not a V6. It is an in line 6 cylinder, not a v style engine. That being said you are probably getting the best gas mileage already. That engine was nit the most fuel efficient which is why Toyota/Lexus dropped it from production(failed federal fuel mileage/emission standards). A cold air intake might help slightly. Lighter tires aren’t realistic as they don’t make many tires for that car, and they are already as light as possible unless you inflate them with helium. I wouldn’t expect to get over 24mpg even with engine mods.

You will get the best mileage in Automatic mode as the computer can tell better to shift than you can. it will shift for peak efficiency.

If I’m not mistaken, your IS has 17″ wheels? If all you’re going to base changes on is to save gas, and not care for performance/handling offsets, then you can try these:

1. cruise control and limit to 70 mph. Unless you’re doing a lot of up and downhill driving, putting and using cruise control is the single best way to bring up fuel economy because without you realizing, when you drive with your foot, you tend to fluctuate the rpm a few hundreds here and there, so you’re using up fuel you should not. Cruise keeps the car more steady. Also, something like every 5 mph over 60, you’re using about 1 mpg more fuel, so keep it as speed limit, or 70-75 mph tops.

2. increase tire pressure by about 5 psi, so that you get slightly less tire contact, but don’t over do it or you’ll bald out the middle first and you don’t want that either.

3. go down to a smaller size rim and wheel. I think you have 225 on 17″ wheels, so drop to maybe a 215 or 205 width, on 16 or 15″ rims. They may look crappy, but if you’re only concerned with saving fuel, then smaller rims and wheels mean less weight.

4. take extra junk out of your trunk. Make sure you don’t have too much spare stuff back there. Carry only fluids you’ll need (antifreeze, wiper fluid, quart of oil). Don’t carry a whole trunk of goodies.

If you do all the above, then I would think you can get to 24 or 25 on the highway with no problems. Presuming that your car and engine are running at peak effiicency. Have you cleaned our your air filters and stuff?

Clean gas filter.

I heard that you get better gas mileage if you press the ECT PWR button which is the square button near the shifter in my 2001 IS300. It displays green on your dash when it’s on. My friend told me this and it’s seemed to help a little.