Fail Emission Test

Ronnie,

Year? Engine? Mileage? Is the Service Engine Soon light illuminated?

Providing some details would help you get a better answer. Without them, I'd say to look first at the EGR valve given the high NOx and the fact that you have changed the other items you listed. Depending on mileage, you probably should also change the PCV since this is an emissions affecting item and is simple to replace.

Good luck!

Bob

Thanks Bob! I've changed the PCV Value. but, still I can't seem to pass. Do, you think the spark plugs are misfiring? About the EGR, I replace that last year!

Bob! I have a 93SL1 3.1 Liter Engine. Service Light is not illuminated! I appreicate your suggestions

I doubt you'll find anyone here who can help you with that engine. I'd venture to say most of us S-series owners, if not all, have the 1.9L.

By far I made a mistake with the engine size. You are right it is a 1.9L.

I seem to recall that the EGR on that year was vacuum controlled. Check the vacuum hoses and make sure they are not cracked/brittle/leaking. You should also make sure the EGR diaphragm holds vacuum. Also, did you replace the gasket and get the bolts torqued properly when you replaced the GR? How many mile since this was done? After checking everything else, you may want to pull the EGR and take a good look to see if it is still OK. The valve should move freely and not stick open or closed. Also, the vacuum line should operate the valve. The gasket seat should be cleaned to make sure there is a good seal and the gasket should be replaced since it is about a $2-3 item.

If you put in the correct plugs and gapped them properly and replaced/routed the new wires correctly and since I assume there are no other obvious symptoms then the plugs are likely not your problem.

Good luck.

Bob

:) He surely knew that and was yanking your chain! Ratbert, you forgot the smiley! :)

Wow! What state requires a twelve-year-old auto to pass an emissions test, California? :(

Georgia! What a headache!!!!!

California requires them for 5-year old cars!