2002 Ford Explorer still overheating?

We just replaced thermostat & gasket & it has been running great all day. All of a sudden the temp spike straight to red line & when I stopped it had smoke coming from under the hood & the resivor was empty. I filled the resivor before I drove it. What could it be now?

1992 explorer running problem?

I have a 1992 ford explorer 4.0, 5 speed manual, 4x4. About a week ago my engine light came on but I didn't notice any performance problems.

A few days later I noticed my idle in the mornings was different. I would start it and it would high idle(like normal) for about 15 seconds and it'd drop real low and stay there… Usually it high idles for several minutes.

Then a couple more days later I noticed a performance difference. I feel I would have to give it significantly more gas to get it going. And a rich running smell.

The engine light will come on and go off while driving… Come on for 2 mins off for 7 mins, on for 10 minutes off for 1 min… Etc.

What could this be? A misfire? Also how can I check the engine light code? It's not an obd2. So I'm unsure lol. Anything is appreciated. If I missed something ask it in the comments and I'll reply.