what should I change and clean before taking it to emissions testing... ...I put in 5 gallons of new gas and that’s about it.
Find someone with a scan tool. Check for "codes", if there are any codes, write them down, and then clear 'em. Use the codes--if any--and the scan tool data stream and diagnostic capabilities to assist in making repairs/maintenance to the emissions systems. The factory service manual has the diagnostic procedures; and many of the manuals are linked-to on this site for free download.
Fresh gasoline with a 20-oz bottle of Techron Complete fuel system cleaner, then DRIVE IT at varying speeds. When that tank of gas is nearly gone, change the fuel filter.
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BEFORE you change oil, drizzle a "uri-ne stream" of water into the throttle body at fast idle (have someone hold their foot on the gas pedal, 1500+ rpm. Faster, up to about 2500 rpm is fine.) Run a gallon of water or more down the throttle body. This steam-cleans the combustion chambers. Pouring the water too fast will cause cylinder(s) to misfire--don't pour so fast, and stop for a few seconds so the wet cylinder(s) can recover.
Really? I can't spell out "ur_ine" because the hyperactive censor on this site doesn't like p_iss?
Then change oil and filter to remove moisture from the crankcase.
Verify PCV valve operation
Verify air filter
Fresh spark plugs, maybe cap, rotor, plug wires
You want to burn through the tank of gas having the added Techron detergent in it before going to the emissions test.
This is a lot to do in a week, if you've got codes to resolve. Good luck.