My timing went out and I took the head off and took it to the machine shop.. I got 16 new valves and put the head gasket back in and hooked everything back up.. When I cranked, the acceleration was VERY irratic. I changed the throttle posistion sensor and restarted and now it is loping constantly at about 3000 RPM.. Did a vacuum test on EGR valve and thats not either!! Has anyone had this problem?!?!