'97 Tacoma Misfire on Starup and Long Grades - 2.7L

Hello all,

Recently, my Tacoma started showing a strange problem. On cold engine startup, she (typically) will run rough for about 30 seconds, and then clear out. Occasionally, this problem will not show up. If the engine is already warm, this problem is also nonexistent.

Recently, it has also started misfiring when going up long steep hills at highway speeds. The check engine light will flash at this point (it does not on startup).

I have replaced the air filter and ran SeaFoam through at less than 1/4 tank. Neither of these showed positive signs.

It throws a code P03000 - Random Missfire, P0171 - System too lean (if cleared this doesn't always come back).

Any insight anyone can provide is greatly appreciated as I do not know where to begin!