car trouble

yesterday i brought my car into a repair shop. the service engine light had been on for several weeks but there didn't seem to be any real problems with it until yesterday morning. it started and as i backed out of the driveway it seemed ok. then i put it in drive and started. it was shaking and then the light started to flash. i had called the dealership a couple of weeks back and they said as long as it didn't flash it was ok but still needed to be fixed. i guess i should have listened. mark finally heard from the dealer and it would set us back $850.00. this is a sad day.