Need Help ASAP

So yesterday i was driving my car and all of a sudden i had a lose of power, and the check engine light came on. I pulled over immediataly and checked the oil, it was very low (considering it was changed 1 month ago). I walked to the nearest place and picked up some oil and put it in. Waited a while and tried starting it again, same thing, still no power.

I had the car towed to Sherwood Chev and they looked at it this morning and told me that the car has the incorrect spark plugs. They are preformance ones and they are about a half inch too short. They are going to try OEM spark plugs and see what happens.

First off i have not done any performance mods other then the cold air intake, and this means that the spark plugs that are in there have been in there for 2 years, since i bought it from Saturn in Calgary.

-How could it run so nice for 2 years and now start causing problems?
-They said it is possible that the Head may have got cracked from this. is this possible?
-Shouldnt the original dealer that sold this used car have checked out the spark plugs when they did the tune up prior to selling it?
-I took the car in to Sherwood back in June saying the car was making a clicking noise when it starts until it warms up and idled a little ruff. When i told them this shouldnt they have checked the spark plugs at that point?


Any help sooner then later would be great cause im waiting to hear back from Sherwood.

Preston