Oil light stays on too long on a cold start

…and it's also possible Wix oil filters aren't what they used to be; see here. I switched to Fleetguard (Cummins' filtration division); their LF-3487 synthetic-media filter is a complete beast. Instant oil light shutoff on startup, and real good oil analysis numbers even after extended mileage. See here if you wanna try some of them.