Yeah I'm having an issue like this with my '93 R32 GTS-t. I'm running a big stereo as well which, when playing beats, increased the gravity and frequency of the near stall/hesitation on moving off from idle and hesitation in low revs.
With this in mind, I started by replacing the battery as it was proper fu**ed. This improved things 10 fold as the new one has 580 CCA and can handle the stereo as well as the cars electrical needs but I'm still getting the occasional hiccup (which 99% of the time occurs when I stop and pick a friend up, but is only present for a few seconds.
I think AFM will be next - I'm gonna give the z32 a clean and see what happens.
If cleaning the AFM doesn't completely eliminate the problem I'd be testing the ignitor chip and the voltage to the fuel pump.
I have new splitfire coil packs, recently regapped plugs and I have recently replaced fuel filter.
I'll let you know how I get on with mine but this seems to be a pretty common issue with the early RBs (20 and 25).