Jordy145

I've got a 2007 f150 with the 5.4 3v. I am having to what appears to be a misfire. Things that have been done (in order) new battery, throttle body and MAF cleaned, fuel injection service, power steering fluid changed, coolant changed, spark plugs changed, all 8 COPs changed. The misfire happens from around 45 to 50 mph (1100 to 1300 rpms). After i had all my plugs changed, ran great for about a week or two, then threw a cylinder 5 misfire P0305 code at 75 to 80 mph in overdrive. That is when i changed all the COPs. Misfire is gone at 75 mph and beyond, but still present at the 45 to 50 mph range.

Is there any way the cylinder 5 misfire could have messed up the spark plug in that cylinder, or is that just wishful thinking?

Thanks in advance,
Jordy

Jordy145

plugs were changed at the local dealer