Can IS 300 run ok on regular gas ?

Salkhan21 · Lexus Owner Joined: Feb 07, 2008 Posts: 2

I would like to know, if its ok to put regular gas in a 2001 IS 300 instead of the premium or the mid grade for that matter?

2JZOneCup · Lexus Owner Joined: Mar 05, 2008 Posts: 3

You could put a lower octane fuel in it but I wouldnt recommend it, it also wouldnt surprise me if you started to hear an engine knock, check engine light, drop in fuel econ, when using a lower grade fuel. And i dont think you wanna deal with any of that stuff! You might be able to get away with it every once in a great while to switch to mid grade but dont consider it long term at all.

n8iveguy · Lexus Owner Joined: Mar 07, 2008 Posts: 2

its not turbo... it should be fine.. but on long road trips and city driving.. use prem

toolbox · Lexus Owner Joined: Aug 09, 2007 Posts: 3

I've been putting regular in my 04 is300 for over 10k miles and it still runs great.. I notice it's a lil more responsive when I do buck up for premium...but barely....

schuss · Posted: Fri May 30, 2008 9:23 am Post subject:

Most all cars built after 1994 with electronic fuel injection, knock sensors and electronic timing control will automatically adjust timing to compensate for lower (and higher) octane fuels.

If you put low grade in it, the computer will retard the timing, meaning a slight reduction in performance and fuel efficiency. Some brands of gas don't put the same detergents in low-grade, so you may be missing out on some engine cleaning, as well.

If you put high grade in (which is 'safer' in that it reduces the likelihood of detonation) the computer will advance the timing, giving you a slight performance and efficiency improvement.

Big differences, like going from 89 to 94 octane, are usually noticable in how smooth and powerful the engine sounds and runs. But small differences in octane will hardly be noticable from tank to tank.

Bottom line, you won't break anything either way - the car is designed to adjust. But if you spend the extra on premium, it'll probably be more fun to drive.

altezzadrifter · Lexus Owner Joined: Nov 30, 2008 Posts: 3

i put over 10k on my '05 is300 and on regular gas and it runs fine but once i put in shell premium gas u can feel a small power increase and increase in gas mileage!!