Is there normally a certain one people pull out

 

the first one

 

If you had the timing advanced it will sound like a miss at idle. Most people will not notice it. I have 3 trucks and everyone of them souinded like they where missing after timing was advanced, bigger injectors made it worse. I started cracking lines at the injectors one at a time to tell which hole was missing. I marked the barrel on the pump that went to that cylinder and started moving that one until I got it out. Don't advise doing this but it worked. Bet if the timing was set back to stock the miss would go away. Not saying to do that.
What I am saying is it should be OK if you can put up with the miss.

 

The miss was there before the advance and I want to fix it bevause the fuel mileage decreased. The truck did sit for 3 years because the old man died and didn't run till things were cleaned out and replaced. It still runs decent but you can hear the miss sounds horrible

 

my old 95 had 140 horse injectors and bigger tubes with lasercut comp dv's and timing at 19.5 and it loped cuz of the bigger tubes but had not a miss at all before the tubes ran smooth

 

when i first got my 1996 my lift pump was shot and i was still able to drive it around the block to park it no miss or problem one bit

 

Well back to this problem and I just talked to the previous owner and he said he didn't do a lift pump. That's my fault I misunderstood. Going down the road you can hear the miss and I just had someone that doesn't know diesels hear my truck and ask if it had a miss so it is noticeable. So all it has is new fuel pump filter and injectors. I really have no idea what to do and like I said before a mechanic for 30+ years on diesels told me a dv but before I spend 250 bucks I want to see how to check certain things any help would be awesome and thank you to the previous answers.