Strange E7 issue

[M54A1]

I have a 97 CH with a mechanical 350hp E7.I bought the truck used, and it has always had a slight stutter or miss, especially at 1400-1700 rpm and it gets worse as engine temp increases. I had the injectors and pump rebuilt. I checked compression, and found #6 was consistently 50lbs lower than the other cylinders. Finally did an inframe overhaul, and had the heads rebuilt. I found a stuck ring on the #6 piston. I was sure this would fix my engine stutter, but it made no difference. The other day I tried cracking the injector lines while the engine was held at 1600 rpm, and when I loosened the #4 line, the motor smoothed out and ran like a sewing machine, until I tightened the line and the stutter came back. What is left to check and what would cause that?

[fjh]

You may have a bad lifter 

[h67st]

Did you look the cam and lifters over real well on the inframe?

[M54A1]

I haven't looked at the cam. I have checked the valve lash several times and haven't had to tighten the adjustment. I figured a bad lobe or lifter would loosen the lash up and cause a ticking sound

[Mack Technician]

Not much left to the imagination after all that engine work. Check the adjuster heights on the rocker arms to see if you’ve somehow managed to progressively compensate (via adjustment) for a chewy lobe. Also recheck your inj pump timing.