It has been a very hot day today and the afternoon has been pretty rainy. We are now at about 90% humidity and I just went to take my truck out, and it was sluggish and misfiring.

Here are the codes that came up when the check engine light came on.

P1300
P0303
P0305
P0171
P0174
P0300

Prior to today I have never had this problem.

 

How old are your wires?

The rain probably threw water up on the wires causing them to arc. I would go out tonight and start the truck and look at the engine in the dark (It will be easier to spot the arcing in the dark) and look for the lights. You can use a spray bottle to help show you where the arcing is.

 

The wires are pretty new, and I don't think was the issue as the truck was sitting there all day in the driveway and it probably only rained for 30 minutes.

 

Well I would still check the wires and plugs any time there is a misfire code even if they are some what new. The wires sit right above the exhaust manifolds and it really can take a toll on the wire boots. I am on my second set of 8mm kingsborne wires in just 65k miles. The first set got brittle and broke in the boot poking a hole when I tried to remove it.

How old are your plugs? Plugs get dirty and go bad. I like to switch plugs out often and never use them as long as the manufacturer recommends. I usually swap them out every 30k miles or every other air filter change.

Also, Check your front O2 sensor plugs for oil. Oil from leaking valve cover gaskets can drip on them and fill them with oil.

 

Do you use parts cleaner to clean those O2 plugs? I need to do mine.