5.7 Vortec missfire issues

[CKVortec]

I'm new to the forum but not new to wrenches or Chevy trucks.
I recently replaced the engine, mostly because I can and I want to be able to get 20 more years out of my 20 year old truck. This is a 2000 heavy duty 2500 with the 5.7 and 4L80.

While I was at it I replaced the distributor, cap rotor, plugs, wires, injectors (MPFI), knock sensor, crank sensor. Everything is primed/painted and pretty. I also have 3 other trucks with the same drivetrain that I have already done the same engine replacement on with no issues.

Here's my issue, even though there are no codes set or CEL I have a seemingly random misfire at around 2100 RPM or so when under a light load (up a hill).
I have a scan tool and here is what I have determined:
the misfires are almost all in the front half of the engine
cylinder number 2 seems to be the worst offender most of the time, but it changes.

What I have checked/done:
valves all readjusted
cam sensor timing set to 0*
O2 sensors cycling rich/lean
TPS reading smoothly from 0-100% throttle
swapped spark plugs
swapped plug wires/distributor cap
swapped injector assembly with an old one
swapped coil, module, map, maf sensors with ones from my other truck
swapped egr valve with an old one

I am running out of ideas, any help would be appreciated.
Anyone know if the cam sensor could cause this?
what about the coil, does it need a good mounting ground? I plugged another one in next to it to test and it ran/test drove the same.

 

[SUBURBAN5]

Have you tested for gasket leaking or cracked head?

 

[CKVortec]

Have you tested for gasket leaking or cracked head?

I did a cooling system pressure test and it held 15 pounds overnight. New long block, so not much chance of cracked heads/block or gasket issues. It idles fine and runs great most of the time, just a few misfires under light load at mid throttle. not enough to set a code.

I think my next step will be a compression test just to be sure.

 

[SUBURBAN5]

Yes compression test and what's your fuel pressure?

 

[CKVortec]

Yes compression test and what's your fuel pressure?

Key on engine off 64 psi, running 55-58 psi rising to 62ish under throttle

 

[SUBURBAN5]

Good pressure. Compression test should tell you how all the cylinders are reacting. I know some caps can be cheaply made. And cause a random misfire. And also depending on the brand of your distributor. But I don't think that's your issue. What kind of plugs did you go with? And did you replace the wires

 

[CKVortec]

Good pressure. Compression test should tell you how all the cylinders are reacting. I know some caps can be cheaply made. And cause a random misfire. And also depending on the brand of your distributor. But I don't think that's your issue. What kind of plugs did you go with? And did you replace the wires

From my first post:
I swapped plugs with no change
I swapped plug wires with no change
I swapped dist cap with no change

I went with delco OEM plugs after deciding it must not like the platinum plugs I put in, no change.
Food for thought, almost all of the misses are coming from cylinders 1-4, so the front half of the engine. Also the front half of the injector assembly/wiring plug, also the longest plug wires.

 

[SUBURBAN5]

Besides that work. Have you done any work on the fuel injectors?

 

[CKVortec]

Besides that work. Have you done any work on the fuel injectors?

back to my first post again and to clarify a little, when I installed the new long block I replaced the old central fuel injector assembly with a new multi port assembly. to troubleshoot the misfire I replaced the whole spider again with a crusty one I had on the shelf, also multi port. Also no change.

 

[SUBURBAN5]

back to my first post again and to clarify a little, when I installed the new long block I replaced the old central fuel injector assembly with a new multi port assembly. to troubleshoot the misfire I replaced the whole spider again with a crusty one I had on the shelf, also multi port. Also no change.

My bad. Just had an issue like this on mine and I think the guy who swapped my injectors crossed 2 legs to the wrong cylinder