Weird sulfur smell from my truck! Help! :/

[Isaiah92260]

I'm thinking it's the truck, when I engage the truck, the smoke comes and goes, sometimes when it's idling. It smells weird, I'm not sure if it is sulfur because idk what to describe it, I know it isn't my brakes because the smoke puffs even when idling, not sure why it would be my clutch, I havnt adjusted it in about 8 months.... I've noticed it the past couple days after I had to parallel park it on a hill, and I was having a hell of a time because it was a tight spot for my long bed.... Could anyone have a idea what it is? Is my clutch burning out? And/or what can I do to fix this problem... Btw I don't notice issues with my clutch engaging, it's a 3 on the tree, it works perfectly fine, just this mysterious puff of weird smelling smoke