mizak82

Hey guys actually sold my Lexus RX300 yesterday to a very nice guy.. crazy enough today he gets these CEL codes... So I want to try and help him out..

Ive had the P0440 code in the past, it was when I ran 87 octane in the car.. 99% of the time put 93 octane in the vehicle.. Could be a coincidence, but maybe I just didnt tighten the gas cap enough after fill up... I got the codes, I checked the cap, gave it a couple more clicks, reset the codes, and put premium in the tank at the next fill up and it went away.. that was over a year ago..

He did fill up with 87 octane yesterday, I advised him to reset the ECU by unplugging the battery for a minute or two so it can start fresh with a different owner..

not too concerned about that one, but since both came on at the same time I figured it may help narrow down the issue or be related..

Now I am concerned and have a question regarding the P0300 random misfire code..

it wasnt accompanied by any other P030-1,2,3,4,5,6, so it wasnt a specific cylinder.. would that eliminate a coil and or plug being the issue?

thanks for your help..

jds4u2

you did check the gas cap, right?

A day or so after Toyota replaced my alternator, the same lights pop up on my truck too. It was the gas cap.

Margate330

Yes, I think you are correct most likely.

Honestly there is no telling what the new owner did to the car.
Reason I say this is because we sold my wife's Mittsubishi convertible a few years ago with 70k original miles in perfect running & driving condition to a young man who called me 3 days later after he destroyed and completely smoked the transmission.

Should've expected it since he drove like fast & furious when I let him test drive it before he paid for it.