Follow the recommendations in the owner's manual. The engine management system has knock sensors and will retard the timing in the presence of pre-ignition caused by low octane gas but that's not the best way to run the engine. FWIW, I use premium or the mid-grade available at most stations.

Not to hijack the thread, but I didn't know the spare was being monitored by the TPM System. Good to know!

IMO If you can't afford the utilities, don't buy the house.

if you cant hear or feel the difference between 87 and 93 octane, then by all means, go ahead and use the cheaper stuff. long term, it will do damage to the engine, and there goes your lexus warranty.

performance wise, driving other cars, there is a definite difference. the premium gives you smoother sounding engine with more power

I have a lexus GS300 year2006 and a lexus GS 350 2007, my son car.
I owned a lexus 1996 and a 97 sold.
What exactly is the SC ? I see rfe to ot a lot of the times.
Lexuspcl88

I have looked and looked around but have not found the answer: This probably a dumb question but... what kind of gas does the GS 350 require? Regular or premium?

Thanks

Premium...

premium all day...

Thanks! I am used to it.. my TL is the same

I always ran regular in my ES even though it said it required Premium with no issues, but with the direct injection and all I wouldn't consider running anything but premium in the GS.

My 1994 SC400 "requires" premium. I have used regular in it for almost twenty years without any issues. YMMV.

So long as you are ok with slightly reduced power and not quite as good fuel economy, nothing to worry about....

I get 23-24 mpg in town with the four liter V-8 in my SC on regular gas.

When I bought my 00 GS 300 the Lexus dealer had a print out from a guy who drove about 30 miles to work and back each day. He had done a study where he ran a tank a couple of tanks of premium and then a couple of tanks of regular. The difference was the regular cost less but got less mpg that the premium ended so much so that the premium ended up being a better deal.

GS requires premium for best performance of the vehicle. I reach for regular every time. Everyone is different and will do as they please.