91 4.3 v6 rough idle at cold start

I have a 91 GMC sonoma /w 4.3 v-6. At start with engine cold, it will start but runs very rough and will not idle till it warms up. After warm, it seems to run very well except for what seems to be idling a little slow. Has been tuned with plugs and dist cap and wires and such. Has a new tps and map sensor. what should I look at next.?