emission failure on an 05 workhorse chassis 8.1 engine

[JCMack]

I am trying to get my 8.1 engine to pass it's emission test which it failed last week. Oil has been changed, air filter new, MAF cleaned, so i am thinking as it runs rich it could be an O2 sensor. I checked for engine codes an found none. How can I check an oxygen sensor at home thanks

[DSDP_Don]

"JCMack"....This is a little confusing. You asked this SAME question on the 5th and got several answers and never responded to any of those posts Same question

If you couldn't find your first post, you can open the link above.

[allbrandauto]

again you need a pro. scanner its not about reading o2 sensor its about fuel trim levels witch is average of o2 sensor readings snap-on and other scaners have workhorse software again what were your readings

[rgatijnet1]

How many miles on the engine? Does it burn any oil? When was the last trip? Was the engine hot when you took it in for inspection?
What failed(CO, etc)?

[enblethen]

Some OBD II readers show the exact measurements of each of the sensors. This should tell you which sensor is out of limits.
my $50 dollar one from Harbor Freight does this. You would need to get the sensor parameters for your exact year. OBD II tester
It could be the idle control valve. Not sure if 8.1 has one. It acts like a choke for Fuel injection.