Sorry this is some what long. Trying to give all the info and I searched all over looking for things to check.
On cold start up, it doesn't hardly want to stay running and I know the ca has its cold start issues. After feathering throttle to keep it running and engine gets some heat, it will idle by itself, but it wants to idle way lean in 17-20 range. Trying to drive it before warmed up isn't possible because it is to lean still in the same range on wideband. Once its up to temp it will run/idle perfect at 14.7. Driving it will do fine too, cruising stays 14.7, on boost it feels good and 12.5ish. After driving, if I cut engine off and restart 5mins later it will go right back to running lean for a few mins, or i can drive it and baby it up to 2nd and hit boost for a second the afr goes back to being normal.
Last year before having to leave it sitting for a while, this issue was present, I checked codes then and there was nothing. Ill admit I haven't checked them again this go around, but I will next time I get a chance to mess with it. Had vacuum leak at IACV gasket last year, fixed it and cleaned valve, which helped a lot with idle once it warm. Fuel pressure was set at 36psi without engine running, never checked it while it was running. I know in closed loop it can compensate for vacuum leak, and I've checked for one with the brake cleaner method with no luck. Coolant temp sensor was swapped from my old ka after having no start issues in cold and it fixed that issue, but still probably going to buy a new one. My o2 sensor isn't the bosch number, but it's one that crossed with that number, only difference was the one I got is skinny compared to the bosch being fat type. Not sure what else to check besides maf and finding a different way to look for vacuum leak.