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Q: 1999 Toyota Corolla, "CATALYST MON INC" on 1999 Toyota Corolla

I have put over 100 miles on it since I replaced a fuel injector and it is the only thing I am waiting for before taking the car to the state emissions test. (Illinois)
What can I do, or what can it be ???
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When a monitor doesn't complete it could be because the conditions to run the test weren't reached, or it could be blocked or delayed for some reason. Code enable criteria is often a good clue for any possible blocking conditions. If the fuel trims are not within a specific range, or if there is a trouble code pending for an O2 sensor or for the fuel system then the engineers often feel that the catalyst test wouldn't be reliable so it gets suspended or blocked.

So look at ambient temperature limits, coolant temperature limits, (sometimes a stuck open thermostat suspends the test) and monitor them in scan data while performing the "drive cycle" which is a published routine that should see each of the tests run in succession.

BTW how many monitors are incomplete at this time, and how many are permitted to be incomplete? Here in Pa your 1999 could still have two incomplete and pass, in 2000 we went to one.
I had 3 "INC" and 2 went away after about 30 miles, The car seems to be running great without and
problems. There are no codes and no engine light. This seems to be the last one to reset. I am now at 120 miles and nothing is out of the ordinary. I just filled the tank and maybe it may make a difference.
Can it be the Oxygen sensor ?? Do I need a new Catalytic Converter ?? I am at wits end, I love the car and it's a great little driver. I would hate to put a bullet in the block to me out of my misery.
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