PRO Flow vs. C&L air meter question, AFR

I have a question about AFR ratio @ idle between the two meters. I have both, and both are calibrated for the 24Lb injectors I am using.
The PRO FLOW has been recalibrated by PRO M. And of course, the orange tube for the C&L. For some reason my combo has always idled better with the C&L.(@ operating temps) Now that I have a AEM Wideband (nice to have) I can see how the meters compare @ idle.
The C&L meter has a AFR of around 14:3 to 15:8. I put on the Pro M and the mix leans out to 16:5 to 18.
Now with the Wideband I know why the C&L idles better than the PRO FLOW, it is not making the car run so lean. I just need to know if any one out there in the Stang world knows how this could be?

I am using an Air Raid Conical Filter. And I am using a SCT Eliminator chip. I just got the chip back from them as they re-flashed it to enrichen the AFR a bit @ idle. I am not sure what is an exceptable ratio is @ idle. According to SCT ideally they like to see around 14:9.

If the AFR now, with either air meter is within an exceptable range, I won't worry about it. It's nice to know that it does that to keep from fouling plugs.

Previously I had a bad vaccume leak due to bad intake gaskets, and could not even see a AFR below 16:9 @ idle.

Rick 91GT said:

Larry can you pull the chip and take readings with both meters, there is no telling what your tuner did with the SCT software.

Is the AirRaid filter open on the end?

Click to expand...

The air filter is closed on the end.