Do you have a way to test the compression? With the prior mention of tapping the valve with the piston I wonder if there is a problem with that cylinder properly building pressure. Since you swapped injectors that to me eliminates the possibility of injector trouble. What kind of smoke are you dumping now? I wouldn't think IP problem here. I think the lack of revs is connected to the fact that you are running on three cylinders not four and some thing is holding it back.