All the other injectors on that bank are pumping just not 7, my confusion is it threw a cylinder default code for 5 and not 7

 

What i would do is just replace all 8 injectors and the wiring harneses. Its most likely throwing a code because somewhere the wiring is bad. Check all the wires and see if any are burned or if anything is melted, its very commom on these trucks. My truck was throwing high to low side open codes on #1 and #2 so i changed all the wiring and it fixed it.

 

Question.. on your original post u mentioned the truck was running normal until higher rpms.. if the injector was bad wouldnt it be running rough all the time? Or do u think you just didnt notice it? I dont know the first thing about the MAP (or is it MAF) on these trucks yet, but i do know if a vehicle is sucking air in past the air sensor, it wont run right. I had that happen on another vehicle where someone tightened a hose clamp on the intake too much causing the intake pipe to slip apart. The opening was PAST the maf sensor, so the engine was sucking in much more air then it thought it was..

Dont know if this will have anything to do with your issue but i am curios about ur injector results.

 

Pulled number7 injector,doesn't look like its worked for a while,ordered a new one, compression in 7 was 350psi, and 430 in cyl5, we'll have to see what happens with new injector , anyone have advice on a budget scan tool that will run dia
gnostic tests,koer ,injector buzz?

 

it's MAP. it's like a boost gauge for the PCM. when it gets to high, (arounf 22 psi on the OBS i believe) it dufuels.

 

Update, I replaced number 7 injector , ran a buzz test and got 6 that sounded normal 1 weak,n 1 strong. However,now cyl5 injector isn't returning oil. Changing oil today and will let run for awhile after, it seems to run alright no more miss, no codes, just confused by the oiling issues ,num 5 returned fine before we changed 7,any thoughts ?

 

Which injector buzzes weak?

 

Think it was 6 but I cant be sure have to retest later