Gas mileage issues

[maximapwnage]

Ok I have a 2000 nissan maxima, that drinks more gas then a V8, especially when i turn on the a/c. I put new plugs in it about 2-3 months ago. She is throwing no cel's. But i know there is a problem because I recently took a trip back home from d.c. to sav., ga and i filled up twice and had to put an extra 20 in the tank 50 miles before ga. border. I love this car but gas is putting a dent in my "Car's trust fund" any advice on how to get my mpg's back would be greatly appreciated

[MaximA32]

When's the last time you did a fuel system cleaning? With Seafoam preferably. How about the fuel filter? How old is that? Air filter too. Keep an eye on tire pressure? Stock wheels? Big heavy aftermarket wheels will suck down the fuel.

[loystock]

Since when did you have poor mileage - before or after plug change? Did you use NGK plugs? Check and clean the entire air intake - air filter (replace if dirty), MAF sensor (clean with zero residue contact cleaner or CRC MAF Sensor cleaner) and Throttle Body (do not spray carb cleaner directly into the TB, spray cleaner into cotton cloth and use it to clean valve and body). Apply a bottle or 2 of Redline Fuel System Cleaner or Gumout Regane (not regular Gumout) in a full tank of gas. Both of these cleaners contain PEA (polyetheramine), a powerful solvent.

[maximapwnage]

thx will do...before and after spark plug change i used ngk if im not mistaken but i thinkk these motors called for two points or whatever they are called on the spark plug and they didnt have any so i used a single platinum ngk

[maximapwnage]

When's the last time you did a fuel system cleaning? With Seafoam preferably. How about the fuel filter? How old is that? Air filter too. Keep an eye on tire pressure? Stock wheels? Big heavy aftermarket wheels will suck down the fuel.

i havent done a fuel sys. cleanign and as for the fuel filter idk i bought the car in feb. air filter still good and i have stock wheels with correct air pressure

[MTZI30]

What was your mpg before and after?