I use to get about 15mpg around town. I then installed LT's, Y-Pipe, MadZ28 tune, and new plugs and wires and my mileage dropped to 10-11mpg. I figured my o2's were bad so I just replaced them and I still get 10-11mpg. Anyone know what my problem is?? This is killing me.

 

wow and I thought getting 15.5 was bad.

 

Something's got to be up with the MAF with that tune. Have them check it again, the Air/Fuel ratios are way off.

 

Keep your foot out of it lol. I had a problem with my brakes rubbing, got REALLY bad gas mileage, you should jack that bitch up and see if the wheels are hard to turn, before you start blowing some cash on parts.

And put in a new fuel filter if you havent changed that in awhile. A new fuel filter is always a good idea.