I am having a very similar issue.
93 3.0. when the temps drop below 50 degrees, the truck starts right up. runs at around 2500 rpm, then as it starts to drop to regular idle, I get a check engine that flashes 3 times, the idle then drops to around 500 rpm, or dies, of its really cold out. then it spikes back up to 2500, and slowly decreases to standard idle, around 1000 rpm. I have checked the idle air sensor, and replaced the coolant temp switch. cannot pull the code from ecm, due to being a soft code. throttle body is clean, maf is clean ,but will clean to be safe.
I'm at a loss at this point. it did it last year in the fall- winter but stopped. started in the spring, and stopped, all summer long. started again in mid november. its getting worse, to the fact that if it dies now, I need to hold the throttle open to restart.
any help will be appreciated.