Off the cuff, check the following:
1. Exhaust manifold. Are the bolts securing it to the engine tight? Spray some water on the joint, while the engine is still cold. Any sign of leakage? Does the manifold itself have any holes? Leaky exhaust makes for lots of noise.
2. Engine mounts. Worn out engine mounts will make your car sound like a tractor. Given the age of the car, it is likely you need to replace them. It's amazing how much difference this makes. Start with the mount that secures the engine to the passenger side fender. This one makes the most difference to the quietness of the ride.
3. Is the noise coming from under your timing belt cover? Check the condition of your timing belt. When was it last changed? Is it loose? This will contribute noise.
4. If the noise is coming from under the valve cover, your valves could need adjustment.
Aloha, from Maui,
Frank
Frank's Friendly Cars
Maui Car Rentalwww.MauiCarRental.biz