In reply to Don Hoots.

Most likely the ECM was reprogrammed…

The Stochastic pre-ignition recall was performed on my 2016 Malibu about a year ago. Since it was performed, my fuel economy seems to have been negatively affected. At my last service visit (oil change) I asked if the recall affected fuel economy. He said it was an oil change only and would not affect fuel economy.
But GM’s website states that the dealer must “Reprogram the Engine Control Module (ECM)”. Was the ECM reprogramed and does it affect fuel economy?

In reply to Robert Franze.

As far as I know, as long as it is DEXOS1 approved, it should be fine.

also, dealer is claiming synthetic blend is what is needed, this article states full synthetic, what is correct?

Did GM promise to pay for increased cost of premium oil changes?