Q: failed emissions test-P0008 and P0017 errors -automatic tear down to fix?

Hi Susan. Thanks for contacting us today. The responsible thing to do first is correctly diagnosing the reason the vehicle did not pass emissions and what is the root source. Unfortunately, OBD-II trouble codes do not diagnose a problem - they simply give a mechanic a starting point to begin the physical inspection. For example, the P-0008 OBD-II code is a GM specific code, that indicates that the ECM detects that both camshafts on either bank of the engine are misaligned with the crankshaft for more than 4 seconds or a cumulative of 50 seconds. This could be due to a faulty timing chain, but also a failed camshaft actuator or actuator solenoid. The other code is also GM specific and tends to be caused by a failed crankshaft position sensor (or the electrical harness). Due to these facts, I think a complete on-site inspection would be a better investment of time and money, as a timing chain replacement is a rather expensive repair.