Service engine soon light

1992 Chevy Blazer, 4X4, auto, V8, 185K miles. Service engine soon light came on twice - both ways making 280 mile trip. Came on about 1/2 way each trip. Checked oil, coolant, hoses, leaks. Runs, sounds, feels, smells the same as always. Light goes out when stop, and doesn’t come back on. Ideas?

Have the computer scanned for trouble codes. If the light was on there should be at least one code stored in the computer. The code(s) will help diagnose the problem. Without a code you’re just guessing.