Hey I got an 2003 Durango with the 4.7 and an engine code of P300, P302 I replaced all the plugs and did some basic cleaning. If starts a little rough, and idles rough too til warmed up then runs great. I get around 15 mpg. I have already replaced the cam sensor last year. Any ideas please Thanks

 

Looks like you have a cylinder misfire on #2 from the codes, Did you replace the plugs with Champion Copper Plugs?

I had an issue where one of my O2 Sensors went bad, and actually threw these codes, of course my catalytic converter was bad as well.

 

Maybe the coil? or you used a different plug perhaps. Maybe a bad gasket somewhere in the intake...or a pcv hose.

 

P0300 Multiple Cylinder Misfire
P0302 Cylinder #2 Misfire

Get the regular cheap Champion Copper spark plugs and gap them to .040 and install. It also could be the crank sensor, but most likely it is the plugs.