Need help with 2001 sunfire

i have a 2001 sunfire, the check engine light came on a few weeks ago recently it started blinking for a period of time then go back to solid shes a lil sputtery on the accleration but theres also a whole in the muffler i know thats not causing the check engine light but im wondering if it would cause the sputtering? also i tried to replace the spark plugs and wires the wires were hot is that normal? i cant get 2 of the plugs out either they will losen a bit but get to a point were they tighten is there anything i can use to loosen them i just dont wanna snap them off. any info would be apprecated.