Been having this issue off & on again for a few years now. When I start the truck up it idles very rough. While driving around town or giving it gas it rides fine. I'll stop at a stop light and it will start stumbling. Idle starts at 600 and drop to 400 over and over again. While pulling away it will hesitate. Also while driving down the road it seems like it misses and it will start to hesitate and shake back and forth sort of like a bucking until i give it more gas. Sometimes it runs great but I always have the start up idle issue.
This started happening when I ran my fuel tank down pretty low and I thought I may have got some dirty fuel in there. So I dumped some IsoHeet, fuel Injection cleaner and the fuel cleaner from Ford, not sure what it is called. Got a bit better. Pulled the plugs and they seem fine, replaced last year. Cleaned MAF, new IAC, cleaned throttle body, checked intake bolts and vacuum lines. No codes besides for my 1445 emission code which I've had for 10yrs now. Checked fuel pressure at rail and it is 36 w/key on and 28 at idle. Also changed tranny fluid and filter since it was about time.
I'm changing back to the motorcraft plugs, wires and fuel filter this weekend. Anything else I should check for? Thanks!

 

Wirelessly posted

I think the fuel psi spec is 44-50

 

Haynes manual says:
35-45 key on
25-35 @ idle

 

fuel filter?

 

Going to change that this weekend along with the plugs and wires.

 

 

So both of my numbers do fall within range. A bit on the low side at idle but still within range. Don't think that would cause the issue, but you never know.

 

Its not fuel pressure if it stumbles only occasionally. Check out the IAC again. MAF also.
maybe EGR or PCV could do that too.

 

possible the pump picked a piece up in the sceen its self, but unlickly it would cause that much. i would bet fuel filter. cheapest part to start with aside the pcv, but i doubt its that

 

I'll be checking everything out tomorrow. I'll report back. Not sure on how to check EGR though. DFPE is only about 6months old. EGR valve and O2 sensors are original w/ 110,000 miles.

 

Probably of no help but when my gas cap was not attached I experienced the same problem, no codes either. I reset the ecu and put the gas cap on tightly which fixed the problem. Never would have thought a gas cap would do that. I still have missing under high load but that is another issue.

 

My crappy day rant so far.
Started off with a Seafoam treatment. Went well. This brought the construction crew from up the alley out to watch the smoke show.
Started to change the oil. First off they do not make Valvoline Max life synthetic blend anymore so I went with Motorcraft blend. Is this oil ok? Drained and then tried to get the filter off. Well it will not budge. Last time I let the shop change it since it was in for an inspection anyway. 6hrs later later it is still not off but it is filled with holes from the old screwdriver method since I do not have a filter wrench since i never needed one, cause i hand tighten like your supposed to not freaking torque it on like they did.
So I took a break and went over to the fuel filter. Relieved the pressure and noticed the little flap in the fuel filler neck does not close anymore. Stuck in the open position. Not sure if it happened the last time I filled it of if someone tried to siphon fuel. Tried to pry it back but no luck. Is it ok to leave it like this? Got the one side off but can't get the other side off with the plastic tool. Not sure if it is 5/16 or 3/8, anyone know? It worked fine the last time but I can't remember which size I used.Well 5hrs later and still not off. Plus i got the good old fuel bath. Thankfully I wear my shop jump suit and safety glasses. But I'm still screwed.
So now I jumped to the plugs and wires. Went great but the plugs were all covered in carbon and oil. Could this be caused by the seafoam treatment? I checked them the other day and they were ok. Nice new Motorcraft plugs and wires. Can't check them since there is no dang oil or fuel in the truck.
Now I moved on to cleaning the MAF, IAC , etc, changing pcv and air filter. All this went well. I actually thanked GOD for this.
I'm stuck though now with a damn stuck oil filter and a fuel filter I cant get off.
Any suggestions guys and gals?

 

Took a little break and finally got the fuel filter off. In 2 minutes. Why couldn't this have happened earlier. Was a piece of cake this time.

Up next! Oil filter. This will be fun.

 

Do you have a big pair of channel locks for the filter. If not you need a pair of these 100% Silicone so heat isnt an issue and like it says they grip mad.

 

I have a pair like that but no luck. The filter is in a bad location where I really couldn't get both hands on it.

I finally went out and purchased a filter tool. The 3 jar kind and a end cap one that u use a 3/8 ratchet with them. End cap would not work due to the filter being so deformed from me trying so hard. The 3 jaw filter removal worked great! That filter was on there so tight even with the ratchet it was a pain. The seal on the filter had a huge indention in it from being so tight.

After I got it changed and refilled i started the truck up. Took a couple tries since I changed the fuel filter but it fired up nice. Took it for a ride and had no issues. I think the issue may be solved. Still concerned with the oil/carbon covered plugs after the seafoam though and the fuel filler flap.

After all the work yesterday my left hand is now tingling from a bit of carpal tunnel. But some beer should take care of that.