I bought a used 2010 GMC Terrain with 28,000 miles on it in April of 2013. Two weeks after I purchased the car I heard a knocking sound and the check engine light came on. Took it to Dealer and they said the car is low on oil. They put in oil. Two weeks later check engine light comes back on. They put it through a test for oil consumption and that they said the car is using an excessive amount of oil. So they had to change out all of the pistons. ONe month later the check engine light comes back on. Dealer calls GM and they say to reset computer… three weeks later check engine light comes back on… GM now says to dealer it needs a new engine computer. NOt an hour after I pick the car up from it lastest stay at the dealer the light comes back on. GM doesn’t know what it is. The mechanic at the dealer is awesome he did some research and thinks the problem is the gas. I now need to put in 90 or above so the engine won’t knock. Not happy right now I didn’t think that I would have to put in a high octane gas when I bought the car. Terrain owners do you have to put in a high octane gas?
I don’t believe it. High octane gas is only needed for high compression ratios. Your engine is not high compression.