So I have a 95 blazer. Have had some work done since it failed the first time I took it. I replaced the spider, map sensor, idle air valve, catalytic converter, O2 sensor. I took it Monday & it failed.

Hydrocarbons were 3.01
Carbon monoxide was 62.47

I really don't know what else to do, to get it to pass. Would like some input on what should be done in order to fix those problems, thank you.

 

How long has it been since you did an ignition tune up? Plugs, wires, cap, and rotor? I'm no expert, but the HC, and maybe CO sounds like it's not burning all the fuel? You already replaced a bunch of stuff, so there can't be many things it could be

 

I haven't done any of that. I've had this truck for a year & have been told I needed to do different things in order to get it to pass. Which is why I got the spider, cat, idle air valve & map sensor replaced.

 

That would be my guess, ignition related. When I was getting my blazer up and running, after I bought it, I had no idea how old the ignition components were, so I went ahead and bought AC Delco cap, rotor, wires, and plugs.

Follow the advice you'll see here quite often, use AC Delco/Delphi parts only. If you check out rockauto.com, you can usually get name brand parts for less than the junky autozone house brand.

 

autozone should have ac delco / delphi but it may cost more