2016 fe350s. Mostly stock. I had the euro map installed at munn racing otherwise only mods are protection parts. Recently I got a "BestDualSportBikes" endcap for $50 off a local guy and put that on. At the "advice" of some online board members I tried adjusting the TPS from .68 to .63 and then back to stock at .582. Regadless of TPS I was having the same two issues. At high altitude the idle would get very low, to the point that it would sometimes die as soon as it dropped to idle. I raised the idle in this situation and when I came back down to my home altitude the idle was 3000rpm according to my aftermarket tach. It had been 2000rpm when I set out but wasn't high enough to keep the bike going at altitude. The other issue is that on throttle off downhills the exhaust pops an crackles like crazy. It sounds like fireworks going off. Is it possible this is all due to the endcap? I do not recall having this idle issue before adding the endcap and playing with the TPS. My rides take me from 4,000ft home altitude to over 12,000ft to give you an idea of the range.