So I just recently had my car serviced by Acura for a Emission Warranty Recall (replaced plugs, wires, distributor cap and rotor, changed oil, etc). I bought some Guaranteed to Pass fluid and Fuel Injector cleaner and put in my gas tank in preparation of passing my smog test for the 2nd time. The gas mileage after the service was drastically improved (got about 340 for one full tank).

Anyhow, I just took out my AEM CAI and replaced with stock airbox and new filter without the resonator. When I was removing the CAI, I remember nudging the distributor a few times but I didn't notice it move or anything. After I finished installing the stock airbox, gas mileage has been much poorer compared to immediately after the service.

I wasn't expecting my gas mileage to decrease upon putting in the stock airbox but it obviously is much worse. Any clues, ideas as to what the problem may be? I'm suspecting that my O2 sensor MAY be bad, but then again, just thinking of different reasons as to why the poor mileage.

Current MODS:
Stock Airbox with STP filter
JDM ITR 4-1
SMSP carsound cat
ITR exhaust

 

Reset the ECU.

Aftermarket intake will give you better mileage than the stock airbox, particularly if paired with a good header and properly sized cat back exhaust.

 

hmm...so maybe I should put my AEM back on...

I just read that resetting my ecu may do the trick. Thanks H-T