P0300 DTC Codes

Question

I'm getting 2 DTC codes. One says P0300, the other says P0300 P. I can't find a code for the "P". What does this mean? The engine fires up easily, but runs very rough for a few minutes, while the check engine light flashes. Then, it's like a power surge, and the engine smoothes out, and the check engine light stays on steadily. I have changed all plugs, and all the coils. I don't know what to do next....

Answer 1

P0300 Random misfire

The P that comes after the P0300 P means that the code is pending, Even though the engine may have smoothen out, there is still a misfire condition and the CK ENG LT is pending the code, either it will come into maturity during a drive cycle or the next ignition cycle,

 When the Dodge set a P0300, the best way to find the condition of the misfire is do a cylinder leak down test, What happens is the cylinder valve tend to cause a internal vacuum leak, rule out a mechanical condition the fix may just be a  valve job.