95 half ton intermittent SES light, check cleared codes?
 

so I was driving home from work today, got stuck behind someone and sat for a minute, once the next lane cleared, i got on it to get past them, and for about ten mins after my check engine light was on. I'm thinking maybe the knock sensor went off cuz of cheap gas or something, but i really don't know. It runs really good, my question is, can I check fault codes that have cleared by itself? I'd like to know what possibly could have set off my SES light, this is my daily driver and if there's any problem I'd like to fix it before it turns into a big one..

I doubt its big. I get it all the time when I get on the highway in my Cadillac AND my Suburban. In the Cadillac it says viscous clutch solenoid cannot engage. In the Suburban it says EGR valve, but the EGR system doesnt work on the highways only during partial throttle application(city driving). So I assume that since the conditions are the same as the Cadillac when it lights up, only on the highway that it is the torque converter lockup solenoid fault.
MOst likely the same in your as a 1995.