lazabby

I'm wonder what fuel type most are using. I don't have a 400h yet but it's my understanding that it takes premium. Anyone using regular in their vehicle and if so any adverse affects?

lexus114

It`s your call,but I would use premium.It`s recommended in the manual 91 or higher octane.So more than likely the ecm is maped for it.

EXP_Cougar

have only used premium in our 400h from the start...

LEXveryG8

I only use Premium fuel for my 400h, but I have friends that use regular, and they seem to be running fine. But, no signs of adverse effects yet? lol not trying to jinx them...lol

okc329

93 octane Shell gasoline. It yields best miles per gallon figure.

jrobe

I have used regular (87 octane) for the last 15,000. No problems. I am done buying premium. The mileage on my last tank was 31.7 mph (mostly city mileage commuting to work).

Kendig

Interestingly, if you compare a 2007 Highlander Hybrid with a 2007 RX 400h, the Highlander is listed as regular fuel, and its engine is identical, right down to the rated HP and torque...

2009 Highlander v6 vs RX 350: identical engines, one difference in rating. The RX has 251 ft-lbs of torque, the Highlander only 248.

claibst

I have been using only regular gasoline in my 400h since i bought it. and at 28600miles is running just fine with regular scheduled dealer visits. I added a trailer hitch and pull my 22.5' center console boat around every now and then too. I am getting ready for my first set of tires and will be getting the Nitto 850 s or the Nitto NT420's. I like the number 420 and they look cooler so that is what I will get if they are available.

herbvdh

I use regular 98% of the time with no problem at all. I have been doing this since I got the RX400h 30,000 miles ago. Every once in awhile I will use 89 or 93 octane I find this is not worth the extra 10 to 20 cents more for a little increase in gas milage. With the vehicle well warmed up running it for hours on the road 65 to 75 mph I was getting 27+ MPG

Cruiter

I have the new 450h that say's run on premium 91 octane. I can't quite come to terms with .30 more per gallon if it isn't really necessary. At Shell, Premium is listed as 93 Octaine and the mid grade say's 91. I used to burn 87 in the 03 RX300 and it ran great. So if the Lexus manual say's premium 91 , do they really mean 93?

With nearly 800 miles, overall average is a skosh above 30.

wildta

I've been using Regular 87 octane for about 90% of the past 85,000 miles and then I started experiencing engine knock. I switched to premium and it went away. My 2008 manual states that I can use 87 but then it also says if you want better performance, use premium. I then check the online manual and it says to use 91. Did Lexus secretly make this change without notifying customers? Anyone else experience similar issues with their RX400h?

claibst

I've been using 87 octane and recently switched to 93 octane due to poor mileage. I'm getting 22mpg, not impressed with the hybrid anymore at 88k miles. Lexus offered to fix my dashboard by replacing it over a year ago and I'm still waiting for the parts to be delivered. I am not happy.

takeshi74

I have no idea if the manual changed over time but many vehicles designed for higher octane can run on lower octane but that's generally as a temporary measure. I've always run 91+ in our RX 400h and all other vehicles designed for 91+.

theory816

It says to use only premium fuel on the gas cover dude.

Lazyj321

My car has about a 140,000 miles and has been run on regular its entire life. I am averaging about 23 .mpg