Had to run my sons 95 Cherokee 4.0 through the emissions tester today here in Boise Idaho. It failed one category at idle..



test results...



2500 rpm test standard test report

O2: 1.0

CO(%) (less than or equal) 1.20 0.63 pass

HC(PPM)less than or equal) 220 212 pass

Dilution CO+CO2(%): 6.0 14.43

RPM: 2500+/- 500 2381



Idle test standard test report

O2: 3.5

CO(%) (less than or equal) 1.20 0.64 pass

HC(PPM)less than or equal) 220 422 fail

Dilution CO+CO2(%): 6.0 12.73

RPM: 775+/- 425 726


After failing, I went home and threw in the set of autolite platinum plugs I had previously purchased since I already had them. put a half can of seafoam threw the brake booster hose since I was already under the hood.. then went and drove it for a half hour and went and retested and the failed HC went down from 422 to 419.



Now that I think about it. My sons jeep does physically have a cat under it. but the cat is hollow because it blew its guts into the muffler last spring. So at the time I didn't spend the money on a new cat. just put a new muffler under it. It also sounds like it has a exhaust leak some where. haven't had a chance to dig into it further yet. It runs good and stays cool. I also have a set of neon injectors that I had intended to swap into it.



Any suggestions to address the issue.