i just got my 04 Civic EX manual one month ago.
After a week the Check Engine Ligth came up.
Codes are 0300, 0301, 0302, 0303, 0304 and 0122.
I was told they are for cylinder missfire.
The car runs smooth and quiet, it shakes very little but it stays on 800rpm
wich i guess its normal when the engine is warm. It pulls normal, i don't know
what to do. Just normal tune up?
Anybody?

 

You should start by checking the spark plugs and the fuel pressure (random misfires) and the throttle position sensor (0122).

 

i changed the spark plugs, deleted the codes,
the check engine light is gone for a week now,
the car still shakes a little... will see, i guess