Top tier fuel does make a difference and is also recommended by GM .I appreciate your response. The biggest concern I keep reading about it the carbon build up on the valves.
Top Tier Gasoline Is Worth the Extra Price, Study Shows - Consumer Reports
Top Tier gas is worth the extra cost, per a study by AAA. CR lists car brands that recommend Top Tier gasoline and gas stations where you can buy Top Tier gas.
Also, check your oil with the engine running once it’s up to operating temperature….