Pontiac Repair: 2003 sunfire misfire, piston rings, oil consumption

Question
My 2003 sunfire developed a misfire with engine light blinking. I changed the spark plugs and noticed one cylinder plug was extremely fouled. I should mention that this car has been burning allot of oil for the past year. I just did a compression check with the results being 170 , 180, 190, and 0 respectively. what would cause one cylinder to have no compression. I've had the car at the dealership multiple times for the oil consumption issue over the past year as it WAS under warranty but thats another story.Any help would be appreciated.

Answer
Hi Shane:

Well the cylinder that had no compression at all is the cylinder with the misfire I would have to say. It can be from a lot of things. does it have any kind of mechanical noise when running click/clack/knock/bang?? with no comprssion at all my guess would be a broken valve,valve spring or a burnt piston or stuck piston rings. If it had been burning a lot of oil it's possable that the piston rings stuck and or scored up the cylinder walls in that cylinder but even so it should have some compression. tis is gonna have to come apart to see exactly what happend. Untill you know what happened it'sa hard to say what the cause of the failure was. these engine as as a whole are usually pretty good and don't burn oil. Sorry I can't geive you an exact answer without seeing the car. Good luck and write me back when you know what happened I'm curious..