Low A/f Ratio Cold Start?

Basically on cold starts or most initial starts after sitting 30 or more minutes my a/f ratio likes to idle around 10.6, when it warms up it goes back to normal 14.5/14.7. It hadn't been doing this before but it seems odd that it wants to do it now. Car isn't throwing any codes either. Do you think I might have a weak coil? I'm not getting any misfiring at worst case scenario I had trouble getting it to start one day after a 40 minute drive but I was also on my nitrous tune and had my bottle heater on, swapped to my motor tune and it fired right up. Car has roughly 130k miles and stock coils still if that helps.
 
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