A/F Sensor Shutdown at highway speeds!?

[digitalasylum7]

Hi, Ive had an A/F Ratio sensor hooked up for well over a year. I temporarily disconnected my ECU, and since plugging it back in ive noticed that while driving at higher speeds the guage doesnt do its "fancy light show" anymore. It only seems to take readings at average street driving speeds, and at idle. I thought the ECU was maybe no good so I tried a spare ECU I have laying around and no change.

Anyone here of this before?

 

[oldman]

ECU needs time to update its high fuel trim.