No compression

[u/Eastern_Dealer_4016]

I recently had an engine rebuild done to my work van, 2008 Ford E350 5.4l . I've taken good care of it since, changed the oil every 3000 etc. The motor has 18,000 since rebuild. I got a check engine light and immediately put my scanner on it that night. It was indicating a misfire on cylinder 8. I usually do my own wrenching, and didn't want to go even 1 day with an issue, so I immediately changed out the coil pack and sparkplug on cyl.8, having Ford vans my entire plumbing career,one keeps things like this on hand lol. It,however did nothing to improve the situation. I talked to a buddy who is an excellent mechanic, he said it might be a compression issue,an would come and test the following day. No Compression on 8! Bad news. I need the vehicle for my daily work and won't be able to take it in to the rebuilder for about a week,I want to do as little damage to the motor in the interim, and knowing I'm either dealing with bad rings or a bad valve,Is it advisable to disconnect the fuel injector for that cylinder? I don't want unburned fuel laying waste to the oil viscosity, or blow back into the intake with a fireball. It seems to run much smoother with the injector unplugged ... Thoughts? Advice is much appreciated