Just wanted to close this post out with a solution to my issue. I checked fuel pressure and noticed that it was dropping intermittently. I pulled the fuel pump and found what looked like red mud in the tank that was clogging the sock on the pump. Once the tank was clean pressure was stable. That...
1996 4Runner 3.4 auto 4x4 with 480k miles.
Cranks strong and fires up quickly. Idles at 1700 rpm when warm. Randomly it will seem to try an idle down. Revs will get to 1200 then go right back up to 1700. Sometimes revs will fall to almost normal, but idles very rough and often stalls...