check spark plugs cap and rotor, and ignition coil. check gaps on spark plugs.check
for blue fire getting through plug wires.if
so check egr
valve could be stuck open. check for intake manifold leaks. if egr
is good and no leaks are found check fuel pressure from pump. if fuel pump and filter are good check each injector for operation. they should open when interjized.
P0300 multiple cylinder misfire. You need to check plugs, wires, coils, injectors........
Cylinder number two misfire.
Trouble code P0306 means: Cylinder #6 misfire detected
multiple cylinder misfire, in cylinders 5,6,7.
A misfire on cylinder #4. See related questions.
I talked to mechanic and he fixed 5th cylinder misfire on Dodge engine by changing chank shaft postition sensor. It came out on code reader though.
p0302: cylinder number 2 misfire. Spark plug, wire, injector, internal engine,
Random Misfire.
Bad spark plug, plug wire. I hade that problem it was a cracked head "Expensive"
Were the spark plug wires replaced? Even a pinhole in a plug wire can leak enough spark to cause a misfire. Try swapping that wire with another similar length wire from another plug and see where the misfire is then. If the misfire moves to the new cylinder or ceases completely, you'll know the wire was bad.
There would defiantly be a cylinder misfire, and rough running. Worst case the valve could hit the piston and do serious internal damage.
you need new plug wires