I have a 2007 f350 4x4 with the 5.4 engine.Had it for 2 years. it has 200,000 km.it started to misfire a bit shortly after I bought it.took it into a local shop and they replaced #1 and #8 coils.i learned from this forum to check the elec. plugs for the coils also,had them check all plugs for the coils and they found 1 suspect coil plug and replaced it. had them put all new spark plugs and change all fluids in the truck.truck runs really good but have 1 issue still.when the truck is started when the engine is cold, it misfires for about 1 1/2 minutes and then smoothes right out.no check engine light at all. and then runs good.after that. while the motor is warm, if you shut it down and then start back up no misfire, runs great.it does this on every cold start.took it back to the shop and they said they could find nothing wrong.the motor must have carbon build up in the cylinders.told me to try putting seafoam in the gas tank and this may or maynot help.i have tried this but no change.now I recently met another fellow who is a ford mechanic and he told me it probably is some build up but in something called egr and or iad ? idle something?i am no mechanic so does anybody here have any ideas what the problem might be and how to fix it.really would like to get this issue fixed,it is a great truck.thanks.