Any great cummins diesel guys on here?

ok guys
i did some more testing and found if i block off fuel lines to injectors individually
when i get to number 4 injector the truck starts like it should.when its blocked off
so im trying to decide on what injector kits to buy????
probably should replace all 6 injectors, but dang they are expensive!!!
any input on who sells the best kits?
Do i go new? refurbished? rebuilt/reman?
prices range from 1100$ to 2700$ plus core charges

thoroughbred diesel?
dales super store?
industrial injection?

would like all 6 injectors ,and high pressure lines , connection tubes?
the tubes only have 10 miles on them, but most kits come with new tubes anyway
any input on companies you have bought from would be great
thanks
Do new and replace all 6. You'll know you've got all new injectors and it'll be good for while. I replaced mine in my '05 at 260k miles and put new injectors. Tubes and lines should be find if they're not damaged, just clean them thoroughly before rebuilding. I believe I bought Bosch injectors, but sourced them from a local dealer (Diesel Sales and Services, formerly known as Pro Diesel).