Q: engine Lopes or runs rougheven after changing plugs in coils

I got my 2000 Toyota seinna this summer. 240,000 miles on it,and a rebuilt engine with broken motor mount. the owner said if you can fix it you can borrow it because my truck was broke down. check engine light was on at that time AutoZone check was timing or camshaft position sensor not knowing what the camshaft position sensor just drove it. At about 247000 miles it began to run rough and at 247500 tried to backfire.the gas mileage dropped fron 20mpg to 15mpg. I checked the camshaft position sensor or what I thought was the center and found the wiring connections to be faulty .after replacing the wire connectors within 24 hours the van was running much worse.back to AutoZone 4 check engine light at this time the code is for misfire 2 and 5 and something else .after installing new spark plugs and 1 new ignition coil the van runs better but still missing what do I check next? oh yes and it needs an oil change which I'm doing today

My car has 249000 miles.
My car has an automatic transmission.