What's the car worth now and what are you prepared to spend for another? How are the brakes, shocks, & exhaust? Is it a standard transmission and could you also be looking at a clutch in the future? How is the body holding up? What will you get for a trade? When the cost of a repair is more than the car is worth it's usually time to say goodbye, but if you buy another cheap one you can start right back in with water pumps, timing belts, etc. Do some serious homework before you make up your mind.