Hey everyone i have done a LOT of reading on here to try and find the problem.. While im driving sometimes it will just buck like someone pushed a kill switch for a second. the truck is a 5 speed so leaving it in gear keeps it running.. however some times it will shut off completly and wont start back up till I leave it alone for about a minute or so. and then its fine again.. I Just changed the CPS and it didnt change anything. while the engine is running i went under the hood and played with the connections to the valve covers. played with the main harness, icp.. and any other wires i could see. I cannot make it repeat the problem.
the only thing that i think might give someone a guess.. is if i leave it alone for a minute it starts up again.. because if i dont let it sit and start cranking it will not start at all. i dont think its a fuel issue because it does it at random speeds and rps.
also oil is full and just changed. batterys are good. any help would be appreciated.. as i think at this point i might have to take it to ford...

 

My truck was Dying when I would let off the go pedal and coming to a stop. WOuldn't refire right away but if I let it sit it would. (hot oil being thin and leaking past the rings) Ended up being the IPR o rings leaking. Any CEL's when it happens? CHeck the tin nut and the connector on the back ofthe IPR as well. It can work loose and cause problems.

 

Could it be lack of fuel, have u cleaned the screen in the fuel bowl? Just a thought.

 

Don't take it to ford, if youre gonna use a mechanic at least use a independant one. What is your fuel pressure? if its bucking while driving it sounds like lack of fuel (i know this because once in awhile i forget to turn my fuel pump on and thats how she acts til i flip on the switch).

 

Don't rule out the CPS even though you just replaced it. There seems to be no real dependable one that is proven.

 

I'm not as familiar with the OBS trucks, but I'd closely inspect the main harness for any signs of chaffing. On the newer 7.3's, it rubs against the valve cover or CCV bracket and when the wire shorts to ground, it's like someone just turns the key off, then back on. Any dash lights flash when this happens?

 

where exactly is the fuel screen? i have not cleaned it.
I will check the ipr nut, i keep forgetting to check it.
as for the harness by the valve cover I checked it pretty good. i had the covers off last week when i did all the glow plugs. the problem started off in the mornings only, i would start the truck and then it would shut off for no reason after a few minutes.. then after a couple times it would run fine for the rest of the day 300kms a day. it got worse after that..
How did you figure out it was the ipr?
also my cps plug in had some oil in it, i blew it out with air and cleaned it best i could.. i was thinking that might still be an issue if the connection isnt perfect... i dont know if oil would affect the connection or not???

 

im not sure what a cel is im assuming the engine light or something staying on. but there isnt anything staying on in the dash.. it all looks normal.

 

The fuel screen is between the fuel pressure regulator and the fuel filter housing. WHen looking at the filter housing the FPR is on the drivers side of the housing. Take out the two 10mm bolts holding on the FPR. No need to undo any hoses, and carefully pull the FPR away from the filter housing. The screen is inside a little port. Mine was completely clogged, cleaning it made a world of difference. But be careful not to drop any of the parts in the valley of death. I dropped screen in there twice, found it the first time and had to buy a new one the second time.

A CEL is a check engine light.

 

well i took the fpr apart and sure enough the filter was clogged right up, cleaned it all out, put it back together and it seems to run really well. ran it a few hours and it hasnt shut off once! Thanks KevinC. i probably would have never checked that! Thanks everyone else as well for your input.

 

No problem, glad i could help!