I have a 2003, F250 SD, 5.0 with a weird problem no one can figure out.


Now it doesn't matter what time of the year it is but after the truck sits a few days when I go to start it up it run roughs. Sometimes for a few seconds sometimes a few minutes then it "straightens" itself out. Recently it took almost a day to fix itself.
No engine codes, no other symptoms.


Any ideas?


Thanks

 

You'll need to give a lot more info than this if you're going to get help on-line.
03 250, so I assume you mean 5.4 not 5.0. Where is all the general maintenance at? A better description of 'runs rough'. Idles rough? Rough under load or not? So rough it won't move down the road? Or just a power robbing miss?

Mileage? Filters, plugs, compression test, fuel pressure, fluid levels/consumption. No hard codes but what has it been scanned with?

There's many good guys on here that'll take the time to walk you through things if you can cover some of the basics yourself and give good descriptions.

 

Sorry about the lack of info. It is a 5.4, its a great truck and has been carefully and lovingly maintained.
This weird "rough running" started a few years back and only does this when it has been sitting for a few days without being started. When I'm out of town I have my wife/son stop by once a day and start the truck for a few minutes. This alleviates the problem. But recently it sat for 3 days without being started, when I did start it it ran rough, shaking and feeling like it was missing but instead of going away in a minute or two it ran rough for about a day. The next morning it was fine.
To be frank its my wife's truck and she guards it like another child. I took it to a shop but they couldn't pinpoint the problem. They were fixated on the problem being cold weather but this "roughness" happens anytime of year. The only common thread is that the truck has sat for several days?

 

something leaking in one or more of the cylinders? gas is unlikely, because it would burn up right away. oil can take awhile to clear up, and slowly get worse because the plug gets fouled.

maybe pull all the plugs and look at them, and maybe using an inspection scope to look in each cylinder?

 

What is the condition of your IAC?