Ok, I have been struggling with my car to pass emissions (failed because NOX was too high) for the last few months, but I finally took it to a mechanic.

Mechanic said everything checked out ok and that the problem was that the EGR Solenoid was not getting enough vacuum from the Throttle Body, He suggested it to be cleaned/replaced.

Could the problem really be my Throttle Body? How can I tell if its bad?

 

you can disconnect the line and feel for vacuum at the TB. more common for the line itself to go bad than the TB though i would think. a good cleaning couldn't hurt.

 

The passages are probably plugged with carbon and other junk. Take off the throttle body and clean it thoroughly with carb cleaner and a rag and Q-tips until it is bright shiny metal again. Make sure all the passages are clear too. Compressed air can help dry it and blow the passages clear too. This is a common problem.

 

Isn't the port on the bottom of the throttle body a source of ported vacuum?? I tried hooking up a vac gauge to that port when I first got my motor running, and was like almost no vacuum... Then the light bulb turned on, I hooked up to one off of the plenum (the one for the hvac and cruise) and it showed correctly... opening the throttle part way showed vacuum at the port on the throttle body...

EGR operates at part throttle anyways, doesn't it?? I would think a ported vacuum source would be better for it anyway...

 

I cleaned out the Throttle Body with Carb cleaner and it still failed NOX!!! Whats wrong with my car!!!!! I feel like selling it and getting a 4th gen!! HELP!

 

any codes?

 

None

 

Oxygen sensor? How old is it, how many miles on it?

Diverter Valve? It may be stuck and always pumping clean air into you exhaust manifolds...