Code P0300

My 2000 Sonata 2.4 check engine light came on and I got this code, so I
replaced spark plugs and the 2 spark plug wires. Code came back, when car
is cold it is sluggish, but soon comes out of it, what else could I do.
Seems if the coils were bad car would not start or run at all.

 

Nope, some can be intermittent. I had that on one of my cars and a fellow
at work just had it on his Ford.

 

First, try to figure out whether you have an actual misfire. This could be
a fuel pressure, crank sensor, EGR, or idle actuator issue.

If you have no trouble code pointing to a specific cylinder, try to focus
on things that would affect all cylinders.

If you can, read the freeze frame data (sensor readings at the time the
codes set) and check your coolant temperature sensor. The engine operates
well on a very narrow fuel mixture range when it's cold. If the coolant
temperature readings are in error, it could cause a misfire.