1999 f250 5.4 4wd, the truck was misfiring so i replaced all 8 plugs with motorcraft, and all 8 coils with accel. it fixed the misfire, but it wasnt throwing a code and i didnt wanna spend the time chasing down the bad coil plug,

however it was throwing a p1485, brake short to battery, and the abs was on and the brakes were spongy. i looked underneath and the ground was disconnected under the passenger side door so i fixed that and no sooner did i do that but a CEL p1401 came on.

im not sure if these are all connected, but it ran great with all the new plugs, i looked and the hoses i disconnected to get in there are all back where they should be. its running off a little from the seat of the pants dyno. help would be appreciated!

 

Good luck with those Accel coils - they are no more reliable than the cheapo Chinese $80 a set Ebay cops.

With a P1401, your DPFE went bad or the electrical harness connection to it is open, shorted, or has a bad connection.