1994 Integra: Strange RPM Behavior

I have a 1994 Acura Integra LS automatic with about 175k miles. I've noticed that something occurs when I'm cruising in the higher speeds. When I'm going about 70mph the RPMs are roughly 3000 to 3500. When I hit the gas to speed up to 75, the RPMs sometimes (not always) *decrease* by around 200 RPMs or so. Then it will jump back up to the correct higher RPM a few seconds later, especially if I release the gas slightly. Please note that I'm not hitting the gas hard enough for the transmission to gear down when this happens. At first I thought that it was just the RPM gauge behaving strangely. But, after doing this a number of times, I can actually feel the engine losing the RPMs ever so slightly. I can't seem to recreate this issue in lower speeds, however. The problem seems to be getting worse lately.

Could a dirty or clogged fuel filter be causing this (I had the fuel injectors cleaned just last year)? Any other ideas?