I have loud knocking from my engine after filling up with gas from a 7 eleven. Before I put that gas in everything was fine. After filling up the next morning when I started up my car it started knocking. Then the check engine light came on indicating a misfire in cylinder 4. The knocking gets louder as I accelerate. I have checked the spark plug and cleaned the rockers and lifter tubes. It still knocks and check engine light is still reading misfire cyl 4

When opened manually it closes prematurely. What's likely happening?

the scenarios are all different. today in the automatic car wash the window popped open
any ideas

beteween 50 to 55 its the worst i just picked it up from the dealer it only has 12000 miles and has been this way allthe time they had it a week this last time still no fix