Emissions failure due to obd

make sure the idle is actually part of the test , your car probably runs fine and serves you well but without that sticker it's basically worthless , but we have to save the environment , the polar bears hate you

Is it just the silly CEL readout bulb?

It had a knock sensor fault that was fixed with replacement of the sensor, it's gone through readiness checks and CEL is off now. The EMI tester states "turn vehicle on and let idle", it doesn't pick up the RPM's through OBD connection.

Hmmm...tach and odo operate normally? Then speed sensor is probably ok. What is the CEL code when it recurs? Let's hope you don't have to chase a used ECM.

The CEL hasn't come back on since the bank 1 knock sensor was replaced. I've driven about 280 miles to get the vehicle to go through readiness and see still no CEL. That's why I attempted an EMI. No stored codes and it runs great. Checked the pins on OBD connection and everything checked good.

Weird. Maybe it hasn't booted up completely? Drive for awhile and retest. BTW there's one knock sensor.

What hasn't booted up yet? The ECU?

The emissions sensors.

All readiness components have been completed. That's why I attempted the EMI. I'm pretty sure that covers "emissions sensors".