So I've read enough that if anyone uses regular gas on a G type vehicle, due to the high compression ration the ECU will retard the timings to prevent knocking.

Now if that is correct then....

Lets just say I am about to buy a used G37. If the person previously used regular fuel and now if I start using premium, will the timings go back to normal? If not, what do I have to do to put it back to normal?

This is literally a theoretical question even though it might seem like in a position like this.

 

The ECU's are extremely smart on our cars. (Maybe sometimes TOO smart). It is constantly working to make all the changes needed to have optimal performance from your engine. I'm sure it would do the same in this case

 

Yea man, the knocking comes directly from the gas being used and is usually at very low RPMs.. Change the gas...lose the knocking..

 

Never thought of that to be honest, but shouldn't an ECU reset do?

 

ya will go back to normal with premium gas.