Regular Gas
Thread Starter
Pole Position
Joined: Apr 2015
Posts: 294
Likes: 4
From: CA
Regular Gas
Hey guys,
I'm an idiot. I accidentally put 15L (~4 gallons) of 87 in my IS350 before I realized what I'd done. Then I filled the remaining 26L (~6.9 gallons) with 91 (this Shell had nothing higher than 91). I added half of a small bottle of STP octane boost (the whole bottle is supposed to be good for 80L of gas). Do you guys think my car will be okay? Is there anything else I should do to mitigate any damage it might cause? I guess my biggest fear is getting engine knock.
Thanks guys
I'm an idiot. I accidentally put 15L (~4 gallons) of 87 in my IS350 before I realized what I'd done. Then I filled the remaining 26L (~6.9 gallons) with 91 (this Shell had nothing higher than 91). I added half of a small bottle of STP octane boost (the whole bottle is supposed to be good for 80L of gas). Do you guys think my car will be okay? Is there anything else I should do to mitigate any damage it might cause? I guess my biggest fear is getting engine knock.
Thanks guys
Pit Crew
Joined: Mar 2015
Posts: 153
Likes: 71
From: Georgia
You will be fine. You can use regular if you wanted to, and the engine would "de-tune" itself. You will not do any harm to your engine at all. Now if you had put in diesel, that would be another issue!!
Lexus Champion
Joined: Feb 2013
Posts: 2,954
Likes: 235
From: SoCal
You would've been fine even if you put a full tank of regular without octane boost. Car will adjust itself and you would get less performance.
I know some people with BMWs (even Maserati) that put regular gas in their cars on a regular basis because they are too cheap to pay for premium. Their cars run fine without CEL.
I know some people with BMWs (even Maserati) that put regular gas in their cars on a regular basis because they are too cheap to pay for premium. Their cars run fine without CEL.
Trending Topics
Driver School Candidate
Joined: Jun 2015
Posts: 33
Likes: 0
From: California
I run 87 in my 250 tbh. It runs fine with no weird sounds or mpg drop. Not sure about performance because it's slow af anyways aha. I wouldin't run 87 on the 350 or the 200t though. It's weird how the RX350 calls for regular 87 though 
ClubLexus Stories
Celebrating Lexus & Toyota from Around the Globe
8 Tips for Improving Your Hybrid or Plug-in Hybrid's Efficiency!
Michael S. Palmer
10 Best Lexus Models No One Remembers
Joe Kucinski
TRD Off-Road Premium: Best 2026 4Runner, Except This One Thing
Michael S. Palmer
Top 10 Lexus & Toyotas to Drive Before You Die!
Joe Kucinski
Top 10 Lexus/Toyotas With The LEAST 5-Year Depreciation
Joe Kucinski
Lexus LC500 Convertible Auction: A Preview of Rising Values?
Brett Foote
GX 550 vs TX 550: Best 3-Row Luxury Lexus Family Hauler
Michael S. Palmer
9 Best Lexus Models You Can Buy for Half Price (And 1 You Shouldn't!)
Joe Kucinski
2026 Lexus NX Buyer's Guide: Models, Features, Prices & More!
Brett Foote
Thread Starter
Pole Position
Joined: Apr 2015
Posts: 294
Likes: 4
From: CA
In the morning when it was a little chilly (around 6ºC/43ºF), it did have a little vibration when idling that it didn't have before. Also it feels a bit sluggish, but that could just be in my head.
Pole Position
Joined: Aug 2015
Posts: 249
Likes: 4
From: WA
So I got into a debate with my friends about putting premium in my IS350 and they said its all a gimmick by the car manufacturers to say that it needs premium gas. I looked it up and it says there are cars out there such as the IS350 that require premium versus "recommended." While I firmly believe that if a car needs premium then put premium but other than possibly damaging the engine to a car, are there any other reasons that you should put premium?
Lexus Champion
Joined: Feb 2013
Posts: 2,954
Likes: 235
From: SoCal
So I got into a debate with my friends about putting premium in my IS350 and they said its all a gimmick by the car manufacturers to say that it needs premium gas. I looked it up and it says there are cars out there such as the IS350 that require premium versus "recommended." While I firmly believe that if a car needs premium then put premium but other than possibly damaging the engine to a car, are there any other reasons that you should put premium?
Lexus Champion
Joined: May 2015
Posts: 1,739
Likes: 9
From: Minnesota
So I got into a debate with my friends about putting premium in my IS350 and they said its all a gimmick by the car manufacturers to say that it needs premium gas. I looked it up and it says there are cars out there such as the IS350 that require premium versus "recommended." While I firmly believe that if a car needs premium then put premium but other than possibly damaging the engine to a car, are there any other reasons that you should put premium?