I rebuild engine( all new seals, timing belt and tensioners, heads rebuilt). runs perfect. after about 15k I have been getting these misfire codes. If light didn't come on I would not know anything is happening. The car runs great. I reset light and then 100 miles later the Code comes back. It started out p0304 misfire now it seems to p0301 misfires never get two at a time. Never get flashing cel checked and searched around. Have seen everything from coil PAC to valve problem. Odd thing is my car runs great Checked wires, coil PAC fuel system. Compression OK when rebuilt Help!