I just found that the my exhaust manifold (the 3rd one ive installed) has cracked, in the same spot as all of the last ones have cracked. I have installed the manifolds using a torque wrench and used new gaskets everytime but they seem to keep cracking everytime?!?!? Anyone have any clue what could be causing this?? I drive ALOT, mainly highway miles and its an 01 4cyl auto Rodeo Sport with about 103k miles HELPPP!!!!