I know things... A lot of things.
Join Date: Feb 2015
Motorcycle: GSXR 750 K4
Re: missing at idle, sputtering and cutting out below 5k
Good point about the TRE. Also if clearing the PC5 maps doesn't fix the issue, I'd disconnect it entirely, temporarily at least, just to take it out of the equation. Check your vacuum hoses for rips, or anything that might cause vacuum leaks. Your fuel pump/filter should be ok, since it pulls past 5k rpm at load, but doing a fuel flow test anyway wouldn't be a bad idea. Also, check your battery voltage at idle and at 5k rpms, even though you'd have trouble starting the motor in the first place if you had a charging system problem.
If the bike's been sitting for a long time at the lot, you might have gunked up injectors. After 5k rpm the secondaries come on and they might be helping the situation, although, if the primaries are gunked up, I'd be expecting problems at higher engine speeds and loads too.