Won't pass inspection, o2 and cat's "Not Ready"

[tholmes]

I am trying to get my inspection done on the truck, but both times I have taken it in, they come back and say OBDII says the truck's O2 sensors, cats and a few other items aren't ready yet. The first time they told me to drive it 50-75 miles, park it overnight and come back. That was Friday. I have driven 450 miles since then. I tried again to get the inspection and it came back again as not ready. Anyone have any experience with this or know what the problem might be? TIA.

[ArmyAviation]

never herd of that, drive 50-75 miles then insp the emissions. The vehicle should be at normal operating temp before the emission test, if you O2 sensor was out the check engine light would be on. Most O2 sensors should be replaced around 80k. if your O2's are bad they can cause your cats to go bad

[tholmes]

I've never had the Check engine light on. Only did a ecu reset once (way back around 30K miles). I would think if the O2 sensors are bad, the light would come on and it would say so on the test.

[StuntDriver06]

not ready means a drive cycle hasnt been completed, go do some city and highway driving for about 30 mins each, then try again....

[electricjohn]

There should be driving sequence you have to follow in the owners manual to get your computer (OBD II) ready. How it became 'not ready' is what baffles me.

[StuntDriver06]

maybe an ecu reset followed by only one type of driving, ie, not meeting the reqirements of the ready status....