Hey Toyota friends, I have a failed emissions for the NOx GPM and I was seeing where the location is of the EGR Valve on a 97’ 4Runner SR5 3.4L V6, if this model doesn’t have a EGR valve, would my next replacement be on the mass air flow sensor? Trying to get it to pass emissions. I’ve replaced the spark plugs, the spark plug wires, oxygen sensors, and air filters. If anyone knows how to fix this please let me know.

 

The cat is also involved in NOx reduction. An mechanic experienced with these vehicles that also has an exhaust gas analyzer can tell you what parts/systems may be at fault. Unfortunately, such technicians are sometimes hard to find.... the last one I knew of retired.

 

I don’t think it is the cats because I don’t have that rotten smell like you would normally get when they go bad. It is hard to find a mechanic you can trust but that’s why I’m trying to teach my self