Got a p0300 and a p0316 code on my 03 navigator it is running rough and losing power

CODE PO300 - RANDOM MISFIRE DETECTED. POSSIBLE CAUSES ENGINE HAS A MECHANICAL FAULT.CLOGGED OR FAULTY FUEL INJECTORS.FUEL PRESSURE TOO LOW OR HIGH FUEL SUPPLY CONTAMINATED.EVAP CANISTER FUEL SOAKED.EGR VALVE IS STUCK OPEN OR THE PCV VALVE SYSTEM HAS A VACUUM LEAK.COULD HAVE FAULTY IGNITION COIL OR BAD SPARK PLUG. MAF SENSOR CONTAMINATED IT CAN CAUSE VERY LEAN FUEL CONDITIONS. CODE PO316 - MISFIRE IN THE FIRST 1000 REVOLUTIONS

All codes between p0300 and p0399 are ignition system or misfire codes. To be specific a p0300 code is a random/multiple misfire detected code, and a p0316 is a misfire detected on start up within 1000 RPM. Some of the possible causes for these codes are as follows. You could have a faulty spark plugs or wires. It is also possible that you have a bad oxygen sensor, a bad coil pack, a bad fuel injector, a faulty cam shaft sensor, or even a clogged catalytic converter. If I had to start looking at things to check first I would check all of the spark plug wires and maybe even replace the plugs and wires since that is the cheapest way to start. I am sorry I can not provide more information but these kind of codes are very hard to narrow down without actually having the vehicle here. I hope the information I was able to provide you is helpful.