O2 & Catalytic Converter not clearing for inspection

[Florida]

I have a 2003 Jeep Liberty 3.8 Automatic and am not able to pass my state inspection as the computer shows that both O2 and catalytic converter "readings" are not clearing.
They DO NOT show any error or code, they show nothing. The recommendation from the shop was to drive some more, with specific go to 55-60 miles with 1/2 gas pedal, let coast down to 20 without touching the breaks, drive some more.
By now I have driven an additional ~200 some miles and still no luck.
Since there is no error code, the shop also does not know what to do or look for. Say they never had that happen before.

Anyone here any experience or idea?
Thanks a lot

 

[LibertyTC]

Try to obtain the specific OBD2 trouble code numbers.
Wallmart should have Chevron Techron Concentrate available. Add a bottle or two, and that will clean injectors and valves at hwy speeds.

 

[Florida]

Try to obtain the specific OBD2 trouble code numbers.
Wallmart should have Chevron Techron Concentrate available. Add a bottle or two, and that will clean injectors and valves at hwy speeds.

Thank you I will try the Chevron Concentrate and hope for the best.
On the trouble code numbers, there are no code numbers as far as i know, the mechanic tried two different computers and both do not return anything (so literally blank) for the O2 and cat. They are out of ideas other than advising to continue to drive....

I will post here with the outcome.

 

[Ksat]

I think you mean the readiness monitors for the O2s and the cat haven't completed their tests yet. When an erase is done on the DTCs (or the battery is disconnected for a while), all monitors are reset and need to go through their check to see whether they pass or fail. This can take a while, as certain conditions need to be met before a given test is run. For example, the EVAP monitor test will only run when the gas tank level is reported at, I think, 3/4" full or greater. If you run your Lib near empty all the time, that monitor test may never run (and the monitor will always be listed as incomplete) regardless of how long you drive the thing. Did you disconnect the battery or erase any codes recently?

In your case, the monitor for the O2 sensors needs to complete (and pass) 1st before the monitor for the cat can be run. If you haven't erased codes or unhooked the battery in a while AND a scan shows there are no codes (pending or otherwise) in any modules, your shop should focus their diagnoses on each of the 4 sensors, as there's likely a hangup somewhere there.

BTW, although I guess it wouldn't hurt, it's doubtful any kind of cleaner is going to help your problem here.

 

[Florida]

Just as an update and to close the topic. I added the cleaner as suggested and returned to the shop/inspection after using about 1/2 the tank with the cleaner and the car now passed the inspection. Whether the cleaner was the reason or not, I appreciate the support and insights here.