OK, I've failed emmissions NOx was nearly double the limit. I don't have the paper with me, but it's something like 1560 versus a limit of 960. Now, I've replaced the air filter, I'm changing the plugs, wires, cap, & rotor. I've run a cup of water through my L03 engine. HOWEVER, I still need to address the EGR. I don't a get a check engine light, and frankly I've got other things I could spend $80 on. Question, does anyone think that just cleaning the thing would be enough, or should I just bite down and buy a new one? Anyone with experience with the Wells brand that Autozone sells versus NAPA versus GM? 157K miles.

Thanks,
Dan

 

An L03 is pretty straightforward. I'd remove and clean teh EGR valve, the corresponding passages in the intake, test the valve with a vacuum source, meter the solenoid, and test the system operation. Some time ago, someone posted a flow chart from a shop manunal for the EGR system diagnosis if you want to search the archives for it.