UPDATE:

Cylinder cancel test:

Cylinders # 1 & 2 - crack fuel line at injector, engine drops RPM like normal

Cylinders # 3 & 4 - crack lines at injectors, little to no change

Cylinder #5 - crack line at injector, slight loss of RPM, but not as noticeable as cylinders # 1 & 2.

So, basically, I need to start by seeing why cylinders # 3 and 4 are having issues, but where should I start?