Failed E-TEST => High NOx ~ Any Solutions?
The Ontario Drive Clean pamphlet states for "High NOx on Driving Test" the possible causes:
* Inoperative/ineffective exhaust gas recirculation (EGR) system
* Excessively lean air/fuel ratio
* Malfunctioning or missing catalytic converter (3-way catalyst only)
* Excessive spark advance
* Faulty Thermostatic Air Cleaner system
* Engine deposits or mechanical defect
* Faulty cooling system
A little insight into my vehicle's current condition:
* When i cold start or even warm start for the most part the car will ride rough to idle then shut-off after a few seconds. Turning it back on and giving it gas makes it eventually hold idle ok.
* The rear muffler is in rough shape though I've patched it with some foil and muffler cement
* The catalytic converter is fairly rusty but doesnt appear to have any holes though the piping entering into it had a couple tiny fractures which i used foil and cement to plaster over.
* When driving the car and waiting at a light it runs fine and mostly doesnt threaten to shut off.
* Last year i replaced all the spark plugs and distributor cap/rotor.
* The fuel filter possibly has never been changed on the vehicle since its purchase back in 1993?
* We consistently drive the vehicle with a very low gas tank and have ONLY ever used Regular Unleaded.
* I went to a mechanic before the E-Test to do an oil change and he said from the sound of the car and such he would guess the EGR Valve could be an issue but he was also a bit concerned about the small fractures just before the cat converter.
What is the most cost-effective way for me to approach getting my vehicle up to standards to pass the E-Test "High NOx"? Can i simply CHECK / CLEAN my EGR Valve and perform some in-house NOx test to confirm?
Is the $150 Canadian Tires diagnosis worth looking into to determine the exact issue(s)?