I have a 2013 Malibu 2.4 ecotec. It hasn't been to the shop yet, Im pretty sure the upper guide bolt for timing chain has failed. It gives code P0016 Crankshaft/Camshaft/timing misalignment/out of sync. Ive replaced the timing solenoid and a few sensors. It now starts, but cuts off after about 2 minutes. Prior to that it wouldn't start. Is there anything else I can check prior to taking to shop and forking out loads of money to having timing replaced along with waterpump and such, incase im wrong. It just crossed 105k miles has had oil an filter changed every 3000-5000miles max. How hard is it to replace the timing chain an part by myself?