Hmmmmmmmmmmmmmmmmmm. Interesting issue. This might sound off base, but have you fooled around with your throttle body lately? Sounds like there might just be too much air getting into one of those cylinders. Either that or too much fuel.

What's up with the injectors? Check the connectors and ensure they are free of anything that might inhibit the electrical charge that activates the spray. You might also want to check the injectors themselves. Cheap way: swap up the injectors and see if the problem moves with them. Then you can narrow it down to which injector(s) are playing games with ya

Good luck. Interesting issue & I'd be interested in hearing the resolution.