So I went to get my emissions done and found that all the sensors (Catalyst monitor, Heated Catalyst monitor, evap sensor, o2 sensor, egr sensor) are post Incomplete. I have reseated all the connections and it didn't help. Should I start replacing all the sensors or is there some other stuff I need to check too? Any help would be great

 

Has it all been redone with a tune?
Give us a little more info on the car....what modifications have been made?

 

Its a 99 and pretty much stock. the only thing it has is a K&N filter in it. I don't drive it alot and was just trying to get it ready to pass emisions because I'm loaning it to a friend and that's when all this weirdness happened. I drove it for about 4 hours today trying to get the sensors to come on, wiggled the connections that sort of thing, but they just aren't registering on the diagnostic computer I have. its actron autoscanner.

 

And the most likely culprit shows itself. Remove your MAF, clean it with MAF or brake cleaner. Reset the PCM by leaving the battery disconnected for 15 minutes and see if that works.

K&N oil is too thin and gets sucked in really easily, and then clogs the MAF causing all kinds of issues. It only takes a slight film to do it too.

 

You'd think it wouldn't even start .

 

It starts and runs okay, I'll try cleaning the MAF and see if that is the problem. Thanks.

 

Huh idk about the k&n oil... Then how would one clean the filter?