I've had low rpm/high gear cruising-throttle issues for a long time now. I'll tweak my own PC3 map and it'll be good but as soon as the temperature swings more than 8-10 degrees, it comes right back. It's definitely a fueling issue and since fueling and timing maps are dependent on TPS signal, it can be a TPS issue too.
I've set mine the best I can for 80ish degree weather and just deal with it the rest of the time. I can do 15mph in 2nd fine in my parking lot, but 30mph in 2nd is all up-and-down and in-and-out of the clutch. PITA.
Currently my daily beater- 30k+ and counting the miles
07 ZX6R, lime green. Bafflectomy performed on stock muffler, disabled exhaust valve, Jumper mod, K&N air filter, PC3 with generic Euro-spec map, NGK Iridium plugs, Motul 300V & K&N oil filter, Healtech X-TRE, Drive Systems Superlite X2 steel sprockets -1/+3, Green EK chain, EBC Sintered HH pads front and rear, Dunlop Sportmax Q2's.