Ok everybody my first topic of the new year is about my buddies 1994 F-250 ECLB SRW 7.3 non turbo 5spd/4x4 she has just over 180k and shes been acting up, ive only noticed this twice and my buddy Garrett called me earlier and it happened again while i was on the phone with him, its a very random problem that so far doesn't seem to have any sort of trend or any frequency to it, what'll happen is the motor will start stumbling as if if its running out of fuel, another kind of odd thing that has happened along with this stumbling, is we were at Oreilly's the other night and happened to meet this mobile mechanic running around in a 97 PSD that hes one some work to, we complemented his truck and he asked about ours e complemented us as well but as he was looking at the truck/talking to us, he claimed that it had a misfire, me and garrett both looked at him like he was out of his mind, ok now I'm not ASE certified but I'm pretty sure i know a mis-fire when i feel/see/hear it and based upon all the other IDI's ive heard on youtube/in person etc. etc. i know garretts truck runs like it should, after the guy claimed it had a misfire and that he could tell just by the sound he said to come listen to his truck, and they literally sounds the same, he gave us his buisiness card and took off after that, garrett began to worry about him saying that and i told him that i felt the guy was bluffing and theres no need to worry, diesels dont use sparkplugs so the only way she would misfire is if the head gasket was blown, which we just changed the oil monday and we also did the atf treatment as we have been meaning to replace the fuel filter since he bought the truck a few months ago, we did use a motorcraft fuel filter as well and she sat for at-least a day and a half and then today we ran her for a good bit thinking everything was all good but even after she sat again for a couple hours she did it twice
i know that was a really long post but i tend to ramble and i felt that some backstory was needed, if anyone has some answers/help it will be much appreciated T.I.A.!!!

 

alsoif i forgot to elaborate on this, i thought maybe its a sign of an injector on its way out, but she doesnt blow white smoke also if you blip the throttle, the motor will return to a normal idle

 

It may have low compression on one cylinder, but it could also be a bad valve guide.