Hey guys, I'm pretty sure of the answer but just want verification. I got the GT-40 crate engine with XP heads and an E CAM, computer went crazy, so I called up JMS and got a chip sent. Installed it and I'm still getting some bucking and the car will kill at idle with the A/C on. I haven't changed my O2 sensors and I blew a head gasket on my old motor. Do you guys believe that this is the primary issue? Can the 02 sensors cause such havoc? Also, maybe an Autozone mistake or I may just be on too many pain killers for my shoulders...but our cars have two 02 sensors, correct? Where are they located? From my exhaust experience I've got one on each side of the flanges near the headers...this guy said they had two as well but one was before the cat and one after? Both with different prices? Any insight? Thanks