[top_down_camaro]

I have a 91 camaro RS convertable, 170K miles.
This car has been maintained and runs like a jewel up until now.
I drove to the store lastnight without any issues. When i came out, the car wouldnt fire, I had fuel for i could smell it without a doubt. I ended up leaving the car and made arrangments to have it towed the next day. Upon arival, surprisingly it started. But while i was letting it warm up, i noticed the idle shot up irriticatly then droped back down 1500, this lasted about 15 seconds.I drove the car home ( 1-2 mile) without any issues. I decided to let the car run in the driveway. After about 10 min, it stalled as if shut it down. It would start back up but once again it would shut down after about 10 min of idle time. Does this sound like an O2 sensor?
I tried to get a code ( if any ) but wasnt succesfull to even get 1 flash. I grounded #6 and #12 post, then tried #5 and #12. Was i checking the right post for a read out?