2001 Dodge Van Trouble Starting Barely Running Very Rough Backfiring Smells

That's what mechanics are for. They get to look, hear, feel, poke, and diagnose the cause. Start by having the diagnostic fault codes read. The sulfur smell is caused by a problem with the catalytic converter, and that suggests a fuel-related problem.

A defective map sensor can result in too much fuel going into the engine, but they don't fail nearly as often as they did in the late '80s and early '90s.