2000 Tacoma 2.7 poor cold start... misfire... then ran perfect...

So I go to drive my son's truck this morning (2000 Tacoma 2.7 with 160K on it) and it fires right up. High idle is great for about 15 seconds. Then I feel a misfire about every few seconds. Never did this before. Always ran perfect. Drove it 4 miles to the paint store and it ran like crap the whole way. No check engine light came on despite it running shitty for several miles. Went in to get the paint, came out and it ran like a top. Drove home 4 miles without a hiccup.

I searched poor cold start but came up with a bunch of unrelated posts.

Any suggestions? I initially thought coil(s) but the fact that it cleaned up after turning it off for 10 minutes has me doubting this diagnosis. Maybe running too lean while cold? Bad coolant temp sensor?