How do I Troubleshoot an Audi 90?

Problems Based on How the Audi Smells
1. Locate the serpentine system underneath the Audi when the vehicle is emitting a strong exhaust odor while you drive. The system may have become loose, rusted or burned out. Additionally, check the exhaust manifold gasket to see whether it still functions properly or whether you must replace it. A leak may also have occurred between the exhaust manifold and the exhaust pipe, or your muffler may require replacement.
2. Check the valve stern seals on the exhaust system when the Audi begins to emit a smoke smell just after you have started the car. The seals may have become damaged or have begun to leak. Also look at the head gasket to see whether it is leaking coolant into any of the engine's cylinders.
3. Find the fuel line assembly, and check for loose or damaged fuel lines or connectors when you smell fumes while driving. Check whether your fuel filter leaks, whether the Audi's fuel tank has become damaged and whether the canister purge valve on the fuel lines leaks. The carburetor and fuel injector may also have become dirty or worn out.
Problems Based on How the Audi Feels
4. Examine several brake components of your Audi if the brake pedal feels difficult to press down. These components include the brake power booster, brake caliper, master brake cylinder, brake hose, wheel cylinder, proportioning valve, brake pads and shoes and brake rotors. Also check to ensure that your brake fluid is at a safe level and that your brake drums are not excessively worn.
5. Examine the brake calipers and brake hoses when the Audi pulls to the left or right as you drive. These parts may have worn out and require replacement. Also examine the steering gear and the suspension coil springs to see whether they have worn out.
6. Inspect the air filter when your Audi loses power to see whether it has become dirty or faulty. Look at the catalytic converter as well to see whether any of the piston rings have become broken or excessively worn. The distributor may also have become worn or damaged and require repair.