At random, cel's come on!?

[wsdrummer06]

I started my car today to 4 cel codes being set off, yet they were not on when I shut the car off last night. they are :

P0300
P0303
P0304
P0420

I know the first three are misfire related and the last is the cat system.

Does anyone know about or has had this combination of codes?

WHERE WOULD I START TO TACKLE THIS???

 

[xci.ed6]

300=random miss'
302=miss 2
304=miss 4

start at plugs

 

[wsdrummer06]

300=random miss'
302=miss 2
304=miss 4

start at plugs

Ya, it needs them anyways so that seems like a good start. Thing is it runs great! Just drove 45 miles without any noticeable issues.

 

[kleen98accord]

Replace your plugs. They'll only get worse.