The most puzzling question so far this year!!!

[nastynissan]

the CO levels on the computer at the smog shop go up and down, way out of the legal limit.. the limit is about 1.0% and it goes up to 7.5% and creaps to 0% and then goes back up.. no difference in rpm's or power. just passing smog is the problem. why does it do this? and yes ive had a tune up. and i searched, "for days."

[180fan]

Ha ha ha. It's one of the first few questions this year. Ok so your CO levels will be dictated by a few things. Your fuel. Run too rich and you'll get more CO, if your HC numbers are high as well, you're getting an incomplete burn and I'd start to look at the injectors for one that's stuck open or a spark plug that's not sparking like it should. Another thing that could be doing this could be your o2, that's one of those parts that will have a signal that will bounce between rich and lean to give a nice median kind of life to the cylinder conditions. There has to be something else that's causing that spike otherwise. I'd suggest looking over the spark plugs and see what they tell you.

[nastynissan]

thanks, ill do that in the morning. how would i know if it is an injector malfunction? im guessing the plugs will tell me.

[pr240sx]

EGR malfuntion