i don't know what causes this, but my hb a lot of the time will have the worst smell inside.. i think it's the exhaust fumes.. is this common with swaps...

i mean smelling some fumes everyonce in awhile.. i understand, but this is almost constant..

it makes me light headed at times.. and normally gives me a head ache...

but then sometimes the fumes aren't even there.. i don't see any exhaust leaks, but u can't always see them...

it's a cat free exhaust... and i've got dc sport headers...

anyone know what to do to fix this... or what it is..??? any suggestions.