can 2007 parts be used on a 2008? Reason for asking: I have a 2008 Chevy Cobalt and the man (mechanic) working on it was adament that it was a 2007. Anythng he does to try and get it going isn't working. It has been 3 months now and I need my car.

Clearly the man working on it is part of the problem and is not a mechanic if he doesn't even know how to determine the model year of the car he is working on. Take it to someone who is qualified to work on other people's cars and who knows how to do proper diagnostics before starting to replace parts.. Have it scanned for trouble codes, do a fuel pressure test, load test the battery. Many parts do work for multiple model years, but some do not, especially electronic parts. Also there are several different drive train options with certain parts being specific to what your car actually has in it for an engine, transmission, etc. Someone who can't figure out what year your car is probably can't figure out which engine is in it and whether it has a manual or an automatic transmission. Good luck. At 156,000 km the car should have lots of life left in it yet.