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Fuel Odor or Drop In Gas Mileage

Your Exhaust Smells Like Gas or Your Gas Mileage is Falling


Symptom: The car uses more fuel than normal, and there is a strong odor from the exhaust. You notice that gas milage has gone down quite a bit. There is a strong smell like rotten eggs coming from the exhaust. You may or may not have noticed that the car doesn't have the same amount of power it used to.

Possible causes:

  1. If you have a carburetor (seriously?), the carburetor choke may be stuck closed.
    The Fix: Repair or replace choke.
  2. The engine may have mechanical problems.
    The Fix: Check compression to determine engine condition.
  3. The ignition timing may be set wrong.
    The Fix: Adjust ignition timing.
  4. There may be a fault in the computerized engine control system:.
    The Fix:Check engine control systems with a scan tool. Test circuits and repair or replace components as required. (Generally not a DIY job)
  5. The engine may be running too hot.
    The Fix: Check and repair cooling system.
  6. The fuel injectors may be stuck partially open.
    The Fix: Replace injectors.
  7. There may be an emission-control device that is not working properly.
  8. There may be some type of ignition problem.
    The Fix: Check and replace distributor cap, rotor, ignition wires and spark plugs.
  9. The fuel pressure regulator may be operating at too high of a pressure.
    The Fix: Check fuel pressure with a fuel pressure gauge. Replace fuel pressure regulator. (Generally not a DIY job)
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