fail smog check on a 93 gs300 ,check station said to check egr valve . here are the test results, NO (ppm) max allowable is 978,my lexus measured 1174

 

Turboelmo,

Do you have a turbo on your GS as your user name implies? Give a little more information about your car - mods, miles, etc.

Also moving this to the 1st Gen section.

 

Just as DaveGS4 said, we need to know more about the mods on your car...the turbo may be causing a malfunction with the egr. How many miles? Maybe the vacuum lines are cracked or not connected properly. Maybe the egr valve is clogged, like mine was. Give us as much info as you can about your engine.

 

this gs is all stock, has around 120k miles,if the egr is clogged what can be done ,

 

After unscrewing the egr from the metal pipe beneath it, I just sprayed air-intake cleaner into the egr valve and the large tube that it connects too. Not too scientific, but it worked. Also, make sure the vacuum tubes are fully connected and not cracked...maybe a vacuum leak somewhere. If you can get hold of a vacuum gauge, you could easily test this. Maybe the vacuum module is punctured.

You should check the electrical connection to make sure it is not loose or that the contacts are not dirty. If it is dirty, clean it out with an electrcial connection cleaner, which can be bought at an auto parts store.

If those don't work, you will have to take it to a shop and have them perform a diagnostic on the egr system...Pep Boys (I know, but it's the only place I can think of) charges $65 for a diagnostic.