P0300 Diagnostic Code - Random Misfire
Symptoms.
Engine may stumble or miss
Engine may be hard to start
you may notice no issues
Cause
Failing spark plugs or spark plug wires
Bad coil or coil pack
Failing oxygen sensor(s)
Bad fuel injector or more than one
Stuck exhaust valve
Bad catalytic converter
EGR valve or valve passage clogging
Bad camshaft position sensor
Bad PCM or ECM
The Fix
Best first action is a tune up, new plugs, wires, inspect all hoses and wire connections then reset the code. If it returns you will need to narrow it down to a system, coils and coil packs should be tested, catalytic converters for function ( do you smell rotten eggs?). A misfire that jumps cylinders could indicate a lean condition, do you have any other codes along with the 300? this will help clue you in to the source, check valve function to make sure they are opening and closing fully.
This is probably pone of the most difficult codes to troubleshoot, so start with the basics and work your way into the more expensive options, in many cases a good old tune up solves the problem, back it up with a fuel system cleaning and see where you stand.
P0300 : multilple misifreP0302 : misfire cylinder #2Check plugs, wires, injector, compression, etc.see related question below.P0300 : multilple misifreP0302 : misfire cylinder #2Check plugs, wires, injector, compression, etc.see related question below.
You have connected the wires to the wrong plugs.
P0300 means random misfire detected which probably has to do with the spark plugs or the plug wires
try the moduel
check the coil pack
P0300 multiple cylinder misfire. You need to check plugs, wires, coils, injectors........
I would replace the spark plugs after 50K, the wires and plugs again at 100K.
you either did not gap the plugs to spec or you put this wires on wrong
try changing the spark plug wires also
Do a compression test to determine condition of engine internals
you have 2of the plug wires on the wrong plugs or distributor cap
You may have switched the ignition wires when you changed your plugs. I did this once and my kia started, idled terribly, then stalled after trying to drive. Go back and swap the wires that fit on top of your plugs and see what happens.