My service engine light is blinking, my Disco II is not riding as smooth as it used to and I lost about 100 miles a tank in gas. My codes read; 1300 0301 0300 0441 0308 0305 0306. I looked them up and they are cylinder misfires. I change the plugs with bosh +4 platinum and the wires with 8mm magnacor. However, I still have the same problem. My discovery is a 2001 with 120k miles. Is there any way out of this problem I have. I am spending way too much a week on gas. Thank you.