need help please thowing code but no blinking light

whats up everone when i drive my car above 1900 rps check engine light comes on and when it drop’s back down it go’s away every time. and when the light is on the cpu does not blink and its 1990 ls auto

is the car stock form and have u mod anything?
Does this only happen when driving at 1900 rpm or will the cel come on too if u keep idling at 2k rpm for awhile?

Check for loose o2 sensor plug/wiring. Check around the engine bay for any sign of loose or rust wires. Did this just happen out of nowhere?

Correct me if I’m wrong but, if everything else checks out as far as connectors and the like, then the FSM says to replace with a known good ECU and replace if that fixes the light on/light off problem. Also known as the no code but light on symptom.

it does it at 1900 rpms and above and the only mod is coil overs. i just got the car so dont know how long its been doing this another thing i just notice is my clock on the dash the min numbers keep going up like its haunted kind of funny thow