We have a 2010 Ford Focus with 150k on it. A month ago I thought I could smell antifreeze getting burned off. 2 weeks ago the wife said the car was sluggish. I drove it and didn't feel anything. Sunday the wife was headed to town and it would barely go. Check engine light came on and when I got home from work the coolant reservoir was empty. CEL cleared. Filled it back up and made an appointment. Today I tried to take it to the appointment and it was missing bad. Limped it there. Code says Misfiring on the #4 cylinder. Pull the spark plug and there is antifreeze on top of the piston. I figure head gasket or cracked head. Got a call in to a shop about repair estimates for each. In your experience how much money will it take to fix that.