P304 code on 97 Tib?

Ok I got this code on my sons tib and it states that is a #4 cylinder misfire. I checked vacuum lines airflow sensor and all where good. Changed spark plugs #1, 2 , 3 were orange (lean i believe) and 4 was black almost looked rich so i did a compresion check and all were over 180 psi. I also unplugged the vacuum going to the fuel presure regulator and it didnt change the way the car was misfiring so we will pick a new one up tommorow. My question is if anyone had this problem and found a fix could you help a guy out so Ican look for that stuff as well? I dont know about the converter but could it cause this problem as well? Can i just punch out the converter on this car or will it effect the o2 sensors? Sorry for the overload thanks in advance!!!!

It was #4 spark plug wire!!! Easy fix and first thing I tried!!!

It was #4 spark plug wire!!! Easy fix and first thing I tried!!!:banghead: :banghead: