So after getting an e-tune I was expecting the mpgs to go up a little bit as my AFRs were a little rich to begin with, but they've gone the other direction and arnt looking as nice as I was hoping. Primarily its in the city that I'm having the biggest issues, highway is about the same as before the tune. Im seeing about 15-16mpg in the city, and I was looking at the AFRs and on light acceleration they seem to be pretty rich (12s and 13s)

My question is if it would be okay to lean these areas out a bit to get closer to stoich? Or is light acceleration supposed to be somewhat rich?

Mods are in sig (N/A w/ bolt ons & 4.77s for you phone users)

 

at light load you should be running a lot leaner than in the 12's or 13's. do you have the closed loop o2 feedback setup on the aem?

 

That is what I was talking about in the Crappy Tune thread.

 

I would guess that you have an intake with a strong resonant hump at 100% throttle, which leads to rich AFR's much less than 100% (still at high load).

 

Ya Im running the AEM V1 w/ an external wideband, so it has o2 feedback, but the O2 FB rich/lean limit is +/- 10% so I dont think the current fuel levels are close enough for them to kick in.

As for the intake, I'm just running a simple K&N FIPK

 

^^ I will when I can, the car is currently in the shop. But awesome service by this guy right here! E-tune is my best mod by far