Yep could be anything burning in there. You should be able to smell the fumes in the bay if cracked. You may be able to see cracks in the header if there'* a leak. You can use a mirror to check hard to see places. I would think, yes, a leaky manifold can create problems if it gets bad enough. I would think it would work on the same principle as back-pressure. If theres a crack theres exhaust flowing without retriction there by decreasing back pressure blah, blah, blah. I may even create turbulance in the flow of exhaust that may have ill affects as well but then I'm not sure if that could create a problem on this car.
92' SSEi Green w/ Tan interior (Sold)
66' Jeep J2000 Gladiator Step-Side
88' Chrysler Conquest TSi AKA Mitsubishi Starion 133k Modified 2.6l Intercooled Turbo @12psi RWD w/LSD