P0133 code slow response error

[lovemycarM35]

Ok I got the SES light on in my M Sunday had AutoZone pull the code P0133 AF sensor bank1 passenger side took it to my mechanic and he side its a soft error
not hard so I should clear the code if it comes back then replace the sensor this all happened after running 87 shell gas in my car I never run that gas only 93
the car is running mint should I just replace it or wait and see it the ses comes back on thoughts ?

[Ilya]

I'd definitely wait and see. Also, IIRC, this may be related to the gas cap not being seated properly or something? I'd reset it, fill it with at least 89/91, and make sure cap is clean.

[lovemycarM35]

Thanks for the replay IlyaKol I'll give that a shot first, maybe I should replace the gas cap

[Larz]

I would also wait instead of just replacing something that is probably working correctly (the code did not indicate a failure of the sensor). These cars have very finicky and quite complicated computers and possibly changing to a lower octane sent a bit of confusion through the comp. Making sure the gas cap is screwed on properly and just for 1 click (as Ilya suggested) is also a great idea. Using 93 octane as you usually do, is probably best for the car as well.

Just as a side note, the difference between the cost of 87 and 93 octane is really not that significant when you work out the math. Let's say you burn 5 - 6 tanks of fuel each month, and the added cost of 93 octane is 15 cents / gallon. That works out to about $15 - $20 per month. Although that is not huge, it is still $20 per month. You can cancel out that expense quite easily by taking a home lunch to work 1 day each week, or washing your car in the driveway instead of paying for a car wash, etc.