I've got a 2006 Mustang GT With 150,000 miles on it. It runs amazing 99% of the time. Every now and then, I get a misfire that sounds horrible. It throws a P304 code, causes the check engine light to flash, and makes a horrible knocking noise with the misfire. It occurs at any RPM, and usually acts up once every 3-4 weeks. I've changed the spark plugs, and have changed all of the fuel injectors. I thought I had it fixed, but I got a nasty misfire once again that only made the check engine flash, and immediately corrected it's self after about 2 minutes. I'd like to nail down what it might be somehow. But it's difficult with it being so intermittent. Any ideas?