How to fix a check engine light with code P0302? And Pass Oregon DEQ?

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I check the code it pops up P0302, misfire on cylinder 2. I had Spark plugs check and coil changed. After code still pops up. I had a shop do a test to find out what the cause is and was told to check with Ford Dealer. I have good combustion, air flow, gas, ignition. They couldn't find out. I did not take it to the Dealer for the ridiculous price to diagnose. When to a second shop said the same thing. When I had the tune-up the car didnt bring the code up till miles later then recently code P0302 and P0303 code pops up. Reset the computer the only code after 5 miles pops up is P0302. I cant pass the DEQ with the check engine light on.