So my '95 Ram failed the test, for the first time! He said the nitrogen level was too high and that I need to take it to a smog repair place.

what might cause the nitrogen to be high, and is this something easy that I can replace a part, or have my mechanic adjust a setting / whatever??

 

Dang I have California. Around here, 95 and older are exempt from smog testing. At any rate, that can be caused by a number of issues:


Lean fuel mixture
Defective EGR system
Defective catalytic converter
High mileage


I'd start with a complete tune up followed by on of those bottles of "smog" check stuff that guarantees you will pass. But, they probably don't sell that in cali.


https://www.amazon.com/CRC-05063-Gua.../dp/B000CIPUR8

 

Right on for that, I'll get the EGR valve, and a can of that guaranteed stuff and give it a go again! I recently had a complete tuneup including wires so was surprised it didn't pass!