Setup: 99 b20z, internally stock. JDM DC 4-1, AEM short intake, 2.5" exhaust, chipped p28 running stock LS code with the fuel maps adjusted upwards to compensate for the increase in displacement.

Have been tracking the air / fuel ratio with a wideband sensor to see if fuel or a lack of it is causing a hesitation problem that I am having.

At idle, or during steady state cruising, the air fuel ratio rapidly fluctuates between 14.2 - 15.6

For those of you who run a wideband daily, how much change do you have in the numbers? How lean does your car get, and how rich?

With the throttle closed, I've in the neighbourhood of 17-18:1...