Adjusting "Verboten" screw

[cxzsaq]

Thank you.

[cxzsaq]

by the way, how are you manipulating the afr on the top end (highway speeds or anything non-idle..).

[jgerry2002]

You can't change AFR at WOT really without affecting the whole pump/range.

You site idle with the CO screw in the tuna-can

Hence the little modification (Wes ingram "sport" modification) where you can engage the warmup circuit a bit and enrich things slightly at mid-top end.

You could try gradually increasing fuel with the verboten screw a bit, but i think you'll find low speed / light load will be too rich.

FYI I'm at 13.0 AFR at WOT with a 2.2L and a mild cam.

Also double check your exhaust, an airleak there can also cause somewhat lean readings. I had a crack in a header that messed up my readings a bit earlier this summer.

[bnam]

Had not though about the exhaust air leak. I have a 421 header with joints where the 4 go into 2. I'm assuming only joints/leaks upstream of the sensor will have any impact and a leak in the joint just aft of the gearbox will not impact the reading -- or will it?

Byas