I agree with Frenchie here I'm not one for guesses and parts swapping, but a CPS is fairly inexpensive and easy to change.
Your AFV at 85 may or may not be the problem, but it is a problem. The ECM is pulling a ton of fuel out of the bike for some reason. Old O2 sensor maybe?
It would be in open loop at WOT anyway, and the ECM is still adjusting with the EGO. You can use the 'live data' with ECMDroid to check the O2 voltage when riding. It might just be lazy and causing the AFV change. Like I said I don't think its the problem, but it needs to be addressed.
Good luck on the CPS swap, sometimes it's better to be lucky
Edit: I was thinking about this.... what's you muffler situation? any changes to or from stock recently? 4k is about where the active muffler valve activates. Usually not an issue, but with a drastically low AFV of 85-ish it may be combining to be too lean to run well.
Last edited by Cooter; 05-23-2018 at 03:21 PM.