Old man at the Benz dealership says he’s been driving the same car for a long time and usually only puts in 87 octane in sprinkled with 91 every few times. What problems could this cause? Do I have to put in 91?
Disclaimer: I’ve owned (paid off) the car for 6 years and do put in 91, but trying to cut costs.
My 1998 Mercedes ML320 takes 91. The few times I tried 89, a check engine light comes on. I did not read the code but I’m sure it’s a knock sensor denotation code. It goes away after I refuel with 91.