ok guys, im a little new to the diesels, so bear with me. my truck is a 90 model crew cab CHEVY with a 92 12 valve cummins swapped in it.(check out my pics to see some of my toys) i have only had it for about a month and have just been cleaning it up and working out some of the bugs. well 1 problem that i have is that i think the engine has a miss, but im not sure. it seems like it comes and goes. it idles a little rough and if u rev it then it feels rough down low, but seems like it clears up. even when u load it up it feels the same. it kinda feels like it clears up when u stay in it. but its hard to tell, it might not be. i have tryed cracking injector lines to see if i could narrow it down to a single cylinder missfire, but no luck there. every one of them made a noticeable difference, but 2 of them werent as hard. so im not sure what to do next. i dont know if the problem is in the injectors, or could it be the valve springs? the engine is stock, i got to reading on here and found the pump mods, i did the fuel pin grind and love it. i went from 20psi of boost to 30psi. but it didnt help the miss any. so any ideas on where to look?

 

get one of those infared heat guns and check the temp on each exhaust port if one is colder than the others it will be the one missing. Might help narrow it down some

 

o.k. i shot all cylinders with a temp gun. all of them shot 180-190, except for the front 2. they shot 150- 160

 

Have the injectors checked.

 

You might want to try a product called hot shot secret it is supposed to help sticky injectors truckers swear by it. If it works it's cheaper than injectors

 

Where do you get this hot shot secret?

 

Hot Shot's Secret | Diesel Engine Oil Additive

 

You might try changing the fuel filter. That sounds too easy, but ALWAYS do the easiest things first!!!! If you don't have a good supply of fuel, (the filter is plugged) then it will make the engine feel like it's missing.