Wow you have done your part and it should be corrected, right? Can't add much. Suppose you have reset the PCM by disconnecting the battery. Battery has been checked and is O.K. Fuel pump checked. Could the plug wires have become damaged? One member here suggested cam sensor. Sorry nothing else, not much help. When you figure it out a post from you would be most helpful to the next guy on what corrected you issue. Good Luck.
Universal P0300 Misfire Detected Code Video Some things to look at when a misfire detected code happens
How To Test Fuel Injectors - REAL EASY!!
Trouble shooting a misfire, Code P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308 Published on Feb 16, 2014
Misfire Trouble Shooting: 30 to 60 minutes ($50 / $75 / $120)
If your car is running rough at idle or hesitating during acceleration, stalling at idle, there is a good chance that it is misfiring. Most of these car motors function on 100 year old basic principals of a combustion engine. They need the proper mix of AIR, FUEL, SPARK, COMPRESSION and TIMING to operate smoothly, in all of it's cylinders. This video will show and explain how to narrow down your possible problem.
Nitro Year: 2007 (1 of 91,815 sold in 07)
Nitro Model: R/T 4X4 Stone White
CAT-BACK Exhaust, CAI, Projector Head Lamps
Fully-Equipped w/all factory options