A recent AAA report says using Top Tier gas makes a significant difference in preventing intake valve and combustion chamber deposits. From the article-
To measure intake valve and combustion chamber deposits, AAA engaged the services of an independent International Standards Organization 17025 certified engine testing lab to perform an American Society for Testing and Materials standard test on fuels.Among brands tested, non-TOP TIER gasolines caused 19 times more engine deposits than TOP TIER brands after just 4,000 miles of simulated driving.
http://newsroom.aaa.com/2016/07/aaa-not-gasoline-created-equal/
I use Top Tier gas, because I figure it's got to help, but am surprised that they found it made that much difference.
To measure intake valve and combustion chamber deposits, AAA engaged the services of an independent International Standards Organization 17025 certified engine testing lab to perform an American Society for Testing and Materials standard test on fuels.Among brands tested, non-TOP TIER gasolines caused 19 times more engine deposits than TOP TIER brands after just 4,000 miles of simulated driving.
http://newsroom.aaa.com/2016/07/aaa-not-gasoline-created-equal/
I use Top Tier gas, because I figure it's got to help, but am surprised that they found it made that much difference.