Well I recently changed my spark plugs 05 fx4 everything went well only broke one, anyways I drove it past couple days everything was good. Now on occasion the truck takes multiple cranks to fire up and when it does fire up it runs rough for a few seconds. Truck runs fine (runs better than before changing spark plugs) just have no idea why it some times doesn't want to start. No codes stored either. I left the key to the on position for about 5 minutes (read the injectors like to leak in the 05) models it fired right up but if I leave it idle for a while then shut it off for a few minutes it seems to not want to fire up some times. Any ideas?

 

was having the same problem with my 05FX4...wound up being the FPDM do a search on it. lots of info available

 

check the FPDM above your spare tire, they are good for corroding and internally shorting out due to water getting in them. also when did you last change your fuel filter?

 

I've changed both parts u guys are talking about. Fpdm its a dorman which mounts with rubber bushings so its not on the metal and fuel filter was replaced not to long ago. This problem didn't start until I changed plugs and it doesn't do it all the time. I think I'm going to disconnect the battery to reset everything again. I did have the pcm unbolted from the firewall when I changed the plugs also disconnected the injectors to make room to change plugs but everything is plugged in. I also used dielectric grease when I put the cops back on. I did use nickel anti seize on the plugs but only around the part that gets stuck in the head (not on the tip of the spark plug). Just something to drive me nuts and make my truck look like a pos lol

 

Check the crank position sensor. If I remeber right someone had a similair problem not too long ago and thats what it ended up being.

 

I will keep that in mind thanks. I did do a search but seems like when that fails it stops spark all together but I guess if it does malfunction occasionally could be my issue. I just don't want to keep throwing money at it if I don't have too. Would be nice to swap it in on a new 5.0 or 6.2 lol