I appreciate all the input. I used to get 18-19 mpg, after all the mods. I drive the same distance to/from work everyday and noticed a sudden drop in mileage, like 14-15. I have done everything already suggested and more. I changed both front 02 sensors, filled tires to max pressure, new fuel filter, sea foamed it twice through brake booster, put in a new EGT, removed and cleaned throttle body (EGR ports were totally clogged), changed IAT, put in fuel injector cleaner, new air filter, new MAF (it threw a code) and probably a few more things I can't remember. I noticed a good improvement after changing the 02's, after installing EGR and after cleaning the TB. Each time though the mpg improvement only lasted a few days until the computer could learn to make the air/fuel mix rich again (I'm guessing here) and therefore consume more fuel. I'm running out of ideas and with gas prices so high it's killing me! I know something is wrong, it uses alot of gas just going across town. Will a scan tool like an Actron tell me if I'm running too rich?