Bank 2 running lean (p0174)

[alwaysdrinkin]

Hello, I recently took my 97 explorer 4.0 sohc to air care where I failed due to high nox emissions. Shortly after the CEL came on. I scanned it and received the p0174 code. I have researched online and found the problem may be a dirty/faulty maf sensor. My question is, if it is the maf sensor and I repair/replace it, will that lower my nox emissions. Are the cel and failing aircare tied together? Thanks

 

[2000StreetRod]

NOx emissions

NOx emissions prior to the catalytic converter increase with air/fuel ratio until maxing out at about 15.2:1 (lean). The catalytic converter is designed to keep NOx low up to 14.7:1 but allows NOx to increase rapidly above 14.7:1.

Cleaning the MAF sensor may not change your lean condition. You may have an intake leak allowing unmetered air to enter the engine. Leaking upper and lower intake manifold gaskets is common on the SOHC V6.

 

[dav9194]

I always try the leak/rpm/carb cleaner test.
Use a scanner for optimum results.
Watch rpm and spray SMALL shots of carb cleaner around intake manifold areas such as bolts and seals that may have gotten bad. I had one that I got back from Ford and they had allowed the NEW intake manifold gasket to lay over when reassembling a thermostat housing replacement. Check out othe areas around throttle body and ANY POTENTIAL places that pull vacuum.
Please go slow, remember to vent areas well between sprays as this can flash over nicely when engine warms spray on outside of engine. Small spray/ watch for RPM Gauge change.
Very small changes are Important to note. Remember that regular/irregular changes are normal ideling. Irregular/regular (sprays) are a leak.
Helps rule out vacuum leaks fairly fast and you can move to next. Like sensors.