as a newbie to the ford 5.4 i recently came up with a problem i know nothing about and hope i can get some advice. i had to drive through some deep water as there was no alternate route, afterwards i started to get a shudder at low rpms and idle. then my service engine soon light came on. the code read cylinders 6 and 8 misfiring. im wondering if theres an easy way to remedy this(other than not driving through water) or do i need to change out the plugs. i just bought the truck and it has 110,000 miles on it. it also has a k&n air intake which i took apart and cleaned out. any help would be greatly apprieciated. thanks and merry christmas!