Random misfires on random cylinders -
Air - bad air filter, bad or dirty MAF sensor, dirty throttle body, unmetered air leaks on air intake.
Fuel - bad fuel filter, fuel regulator, or fuel pump.
Ignition - bad or dirty crank, or cam sensors.
.
Exhaust - plugged catalytic converters.
Action -
1) Replace both air/fuel filters.
2) Clean MAF sensor with CRC MAF cleaner.
3) Check fuel pressure
4) Reset/clear codes
5) Again - Have both the alternator + battery load tested @ local auto parts store for free.
6) Also do a battery drain test done with engine off & key out
7) Have a back pressure test done cheap/free @ a local muffler shop.
8) Monitor