0303 Service Engine Soon code
0303 trouble code on my 2006 Nissan Altima. Leaving work I noticed a clicking noise coming from my engine and my service engine soon light come on. I had to make a stop on the way home and when I started my car again the click turned in to a load knock at first and silence down a bit 5 second later. I had a 5 minute drive home where I noticed the low knock got louder when idling at the lights. Once home I got the service engine soon code of 0303, which I looked up and found said it was a misfire in cylinder #3. I changed my coil pack for cylinder #3, and changed all my spark plugs, changed my oil, and checked all my fluids. In changing my spark plugs I noticed oil on the bottom of my spark plug from cylinder #1. After all that I still have the knocking. Other than a head gasket and valve issue, could I be over looking any other causing issue?