It sounds like your car is ready for a 60K tune up. This normally consists of Plugs+Wires, Timing Belt, Tensioner, Water Pump and a few new seals. On the 4 cylinder the plugs and wires should be easy. The timing belt will be the hard part. My guess is it will probably take 20 minutes to change plugs and wires but the timing belt might take up to 5 hours depending on your knowledge and skill. A service manual is a great investment and I recommend getting one for every car you own if you plan on fixing them yourself. The timing belt should be accessed easiest through the wheel well. Take off the tire and then the spash gaurd, then remove the serpentine belt, then the crank pulley. The crank pulley might require the use of a special tool to get it off. It holds into the front of the pulley allowing you to loosen the bolt. After you get that off pull the timing cover, release belt tension. DO NOT DISTURB TIMING ON CAM GEARS. It would be a good idea to mark there EXACT location. On timing dependent or no tolerance engines the wrong timing can lead to total failure where the valves go through the pistons. Next drain some of the coolant and remove the water pump. Use a new tensioner pulley assembly. Make sure to get all new gaskets and torque everything to spec.