1. Engine Issues:
- Check the engine for any issues, such as worn spark plugs, faulty ignition coils, or engine mounts that need to be replaced.
2. Transmission Problems:
- Listen for any unusual grinding or whining noises that could indicate transmission problems. Check the transmission fluid level and condition, and if necessary, have the transmission serviced or repaired.
3. Exhaust System:
- Inspect the exhaust system for any leaks, holes, or damage that could cause unusual vibrations and noises. Replace any damaged components as needed.
4. Wheel and Tire Issues:
- Check the wheels and tires for any uneven wear, bulges, or damage that could cause vibrations. Make sure the tires are properly inflated and balanced.
5. Suspension Components:
- Worn or damaged suspension components such as shock absorbers, struts, or control arms can cause vibrations and irregular noises. Inspect the suspension and replace any worn parts.
6. Brakes:
- Check the brake rotors and pads for uneven wear or warping, which can lead to vibrations when braking.
7. Driveline:
- Issues with the driveline, such as a worn universal joint or faulty driveshaft, can cause vibrations and noises.
If you're unable to identify the source of the vibrations and noises, or if you're not comfortable or equipped to perform the necessary repairs, it's recommended that you take your 1998 Nissan Maxima to a trusted mechanic or automotive service center for further inspection and diagnosis.