98 cobra running lean with no codes

[jwobbles07]

So i went to a dyno day found that my air fuel ratio was at 14.7 average. well found out that the previous owner installed an aftermarket maf housing and my tune wasn't set up for it. well ordered the correct tune. and got a wide band air fuel gauge. well at idle it maxes out to lean 22.4 then after a minute or two it drops down to 14.5 to 15.1. it stays there at idle and normal driving. its perfect at WOT at 12.5 and gets slightly leaner when the intake runners open at 13.1. So is this normal or not? there are no codes. no vacuum leaks or exhaust leaks.(checked with smoke wizard). correct tune. Don't wan't to drive it if it is this lean. Can some on give me some insight? ive been messing with it for about a month now with no avail.
oh by the way its a 98 cobra with intake, maf housing, cat back exhaust, and x pipe no cats.

 

[mwolson]

That is very normal for a naturally aspirated car. Idle and part throttle should center on a gasoline AFR of 14.4 and 12.5 at WOT is right. It runs very lean when it first starts so it heats up the cats faster. In fact you are seeing the SAI system in action.