So at 41,000 mile i get both codes in a day truck is running like **** anyone know where to start? I know p0300 is multi miss fire and 1635 is a pcm code but just looking for a starting ground

 

After a couple hrs research found that 1635 is axle out of range due to my programmer. Still need help with this p0300.Thanks Terry

 

What engine?

 

well i'm sure living in alaska aint helping any. all that snow getting onto the engine and melts while the engines warm. probably got alot of water down in the plug bores(if v8).
but answer glc's question first. how olds the fuel filter?

 

I found out that my code has changed to a P0301,Its a 06 F150 5.4 i know its number one miss fire but wondering whats the most common problems im going to change plugs and fuel filter tomorrow. Any other suggestions?

 

Pull all the cops replace them, recoat new boots with dielectric grease. You can find cops on eBay for 70-80 dollars for a set of 8. Look for global or uneek.
Auto parts stores are going to be 30-40 dollars each.
Do a search for "spark plug tsb".
If it's been awhile replace the fuel filter.
These motors don't like water on the top.

 

the 5.4 3v uses the dg511 instead of the dg508 (5.4 and 4.6 2v's). all 8 are 135 bucks.
heres the link.
http://shop.ebay.com/?_from=R40&_trk...All-Categories
and yes make sure you view the tsb if your planning on doing the plugs yourself.

 

I changed plugs and running great