Colorado Emmisions

[damo252]

I just took my 89 4.0L cherokee in to get tested, and it failed. The CO levels are three times the maximum.

Does anyone know how to fix this? any help would be great.

[Mopar500]

I had a similar problem in my Suburban.
The cat might be bad or you might want to replace the O2 sensor.
If you can take the temperature of the exhaust, the pipe should be much hotter after the cat than before. If the temp is the same, you have a bad cat.

[damo252]

wow That is something I did not know. thanks for the help