well 2 years and only 5000 miles, not driven much and there is probably A LOT of carbon build up in the engine(hence the CO rating). You need to clean out the engine of all old fluids(oil, coolant, gas, ect). Also, try to put in some injector cleaner to loosen it up. Don't beat on it right away, give it a bit to break in, then beat on it a bit. the carbon needs to be forced out.
