Service Engine Light Flashes

Today my service engine soon light began flashing. My car began to run extremely rough from that point on. I had a tune-up and the mechanic said that one of my cylinders in this 99 sc2 didn't have any compression. He had already done one dianostic and couldn't find the true problem. By the way this was not a Saturn dealer. Does anyone out there have any possible thoughts about what the problem could be. I am a female and don't want to get taken at the shop. Help me if you can.

It is possible the piston rings in the cylinder with no compression could be stuck, but I do not know the full story, so I can only guess. If that is the case, I think you would smell fuel on the dipstick when you check the oil. a stuck valve could cause a loss of compression, but you would probably have a popping noise either out the exaust or from the throttle body, depending which valve it is... I am curious to hear what the mechanic says the problem is...

most likely you have a burnt exhaust valve. a leak down test can determine this. but still the cylinder head will have to be removed before giving you any definite answers