Hello from Arizona. I am new to the world of Buells! I have had my eye on one for a while and finally pulled the plug. Long story short I purchased a 2000 Lighting w/ 13K has aftermarket intake and Vance Hines Exhaust from a guy locally. The PO told me he was having issues getting the bike to run correctly and has been to a shop in Flagstaff, AZ multiple times. Now for the issues, at 1/4-1/2 throttle runs fine till about 2500 RPMs then starts to bog down, spits and sputters, and few backfires, and eventually, the bike will die. According to the paperwork the shop replaced: O2 sensor, temp sensor, new plugs wires and spark plugs, new intake gaskets, fuel filter, and a new coil. The final time he brought the bike in they told him it needed a new fuel pump. I thought no big deal I can easily do that. Before I toss more parts on it I was wanted to get some feedback. Any help would be awesome!!!!!!!

I have checked all of the following since it seemed like the shop wasn't too sure of the actual issue and just tossed parts at the bike.

When the bike is first turned on the fuel pump primes and sits at 50psi then drops to 0 (is this normal?)
Fuel Pressure on startup is 50ish psi (I tested the fuel pump using ECMSpy and got the following error: Failed to Finish active test: Checksum Error. What does this error mean, is this considered a failed test?
I haven't been able to test the fuel pressure while riding the motorcycle
Reset TPS sensor
Cleaned throttle body
Cleaned and test the injectors and they spray a nice clean stream with no leaking
Tested for air intake leaks and I don't hear the engine increase RPMs when starter fluid or similar fluid is sprayed
All wires are intact and no wires have been worn through
Check engine light that came on twice was for the temp head sensor (keep in mind a new one has been installed and that is the only code I have seen pop up in over 2 months)
The AFV is at 150% for both front and rear and the EGO Corr % is also at 150% for both front and rear (I just installed ECMDroid and will try and reset the AFV)