My buddy's 4 runner keeps getting failed for high NOx. 3.4 v6, slushbox, 4x4, non-cali truck, 260k miles or so.
These don't have EGR, we looked on various forums and most people suggest a new front O2 and a MAF cleaning, we did both of those on Saturday and while the NOx lowered, it's still failing.
Any other suggestions? We spent a good 20 minutes going through the vacuum lines, one was suspect on the end but we added a clamp to it and feel it's not an issue.
Next move is to put seafoam in the tank, and do a proper seafoam procedure. He already tried throwing a bunch of HEET in the tank and getting it retested but failed that too lol.
These don't have EGR, we looked on various forums and most people suggest a new front O2 and a MAF cleaning, we did both of those on Saturday and while the NOx lowered, it's still failing.
Any other suggestions? We spent a good 20 minutes going through the vacuum lines, one was suspect on the end but we added a clamp to it and feel it's not an issue.
Next move is to put seafoam in the tank, and do a proper seafoam procedure. He already tried throwing a bunch of HEET in the tank and getting it retested but failed that too lol.