Nissan Repair: 93 Altima, fuel ecomony, haynes manual

Question
I have a '93 Altima that has recently seen a dramatic decrease in fuel ecomony.  What are the most likely causes of this?

Answer
Norb,

Do a tuneup if you have not done one in the last two years.  A fuel filter, air filter and the plugs are the most common cause.  Other things that can cause a decrease in mileage are stuck injectors.  So, check the fuel pressure after you install the new filter and see if it is within range.  Purchase a Haynes manual for really good directions on the tuneup.