To easily merge plugins, you'll need FNVEdit and Merge Plugins XEdit (it's on Skyrim Nexus, but works with Fallout, as well). If it does, I'll close the game and reactivate them 5 at a time to see if I can't replicate the problem, then narrow down from there when I eventually find it.
Usually when I have a glitch I can't pinpoint, I disable all mods and check if loading the game up without them fixes the particular issue. If it's none of hose things, your best bet may to throw your load order up in a pastebin file. I mean I suppose you could try putting, 'tfsmb' into console to toggle motion blur to see if that's the problem. Is your character's head crippled? I think PN adds different visual effects depending on whether you're addicted to chems or not but I'm kind of doubting that's the issue if it's a persistent effect. You've been playing like this for a while? Tried reloading an older save before the issue began, to see if it's effected? That's an easy way to judge if it's some effect brought on by an active.
