ok two weeks ago i took my truck to a ford dealer it had a lean code, a miss fire on #8 and a bank 2 o2 heater malfunction code. they put a new o2 senser in, fixed the missfire, and cleared the codes. i made it about 20miles and the check engine light came back on. two days later i let the truck warm up about 20 min got in to back out of the drive way and blew the #6 spark plug out. took it back to the dealer and they said i have the same o2 sensor code. they said the checked the o2 sensor they replaced and are now chasing wires. oh btw had to replace everything under the dash because of leaky windshield two years ago. any thoughts or ideas or even random stabs in the dark would be nice.