lilativan

Maybe a dumb question but whatever: I have an ‘04 IS300 I was super low on gas, the light was on, so I went to throw $20 in since I had to be to work in fifteen minutes. I told the attendant premium but I looked over and he hit regular instead. Only about a gallon made it’s way in before I looked over and stopped him. He then switched over to premium for the remainder. Is this going to cause a problem? This car has only seen premium its entire life. Am at about 140k miles.

Benoit

As long as the fuel you putted in wasn't Diesel, everything is allright. A concentration of one gallon of normal in between a good 7 other gallons of premium will not be some kind of problem.

But don't put diesel in this car like my aunt did with her Golf.

daddystop

Yeah as Benoit said, it should be fine. You just don't want to run a whole tank, your car WILL ping. These engines have 10.5:1 CR pistons in them, they need to use high octane fuels so they don't get preignition.

Lexyaaaas

iTrader: (2)

cars these days are really advanced. your car will probably pull timing to deal with the increased knock its getting from the wrong octane. I would just take it easy on the gas pedal until you add premium

daddystop

Pulling timing to battle knock raises EGT which shortens the life of exhaust valves.... this is NOT a good solution except in the very immediate short term. If you continue to drive a car like this you will shorten the life of the engine, no two ways about it.

Most oem vehicles have no way of monitoring EGT.

Lexyaaaas

iTrader: (2)

Good info! thats good to know