Cylinder 4 misfire

Hello, a cylinder 4 misfire does not necessarily mean a significant engine failure has occurred. Most often, misfires can be corrected by repairing faulty ignition components, such as a coil and / or spark plug. Testing should be performed to determine if you have a base engine problem by having a compression test performed -- low compression in cylinder number 4 compared to the rest of the engine would indeed indicate a base engine concern with either the block or cylinder head. Frankly -- a service contract that costs $4,500 is extremely expensive, and I'm not sure if it would really save you a whole lot of money. The likelihood of you having a base engine problem at 75,000 miles is pretty small, honestly. Good luck!