Valda, the 2001 XJR has a cold air intake and a smaller supercharger pulley both by Mina Gallery http://www.minagallery.com/jagxp/Jag...c%20pulley.htm, http://www.minagallery.com/jagxp/Jag...e%20intake.htm

Recently, Valda has been flashing "restricted performance," never done it before. When checked, the codes it gives me are:
P1172 System Too Rich - Banks 1 And 2 (Rich Fuel Fault)
P1175 System Too Rich - Banks 1 And 2 (Suspect HO2S)

Am I looking at faulty O2 sensors? MAF sensor malfunction? Or something worse? Your help is most appreciated. Thank you in advance for your time.

 

Does this cold air intake use an air filter that must be oiled? If so, the MAF may be contaminated with that oil.

 

Ditto with Marc. If it were mine, I'd ditch the cold air intake. Regardless of the design, they do little to nothing to going backwards, and often have side effects like these. X-Types are particularly "sensitive" to intake mods. It is VERY difficult to beat the factory engineering on the air intake on any AJV8R.

Also, without knowing exactly what your setup is or how it is working, the MAFS could be pegged. My experience with all Jag engine management designs is that they tend to keep a very short tolerance on air intake metering.

If you can, switch back to the factory intake, clear the codes and try again. Could be the fastest track diagnosis.

 

It wasn't the filter at all, it was that I neglected to properly clean the engine after cutting the old Supercharger pulley. The metal shavings blanketed the MAF sensor, I'm impressed that she even allowed me to start her up. If I had that much crap on my nose, I wouldn't be getting up out of bed.

 

Almost five months later and all kinds of experiments and experts looking at the car, various diagnostics tools and all kinds of hoopla, turns out all it needed was a good MAF sensor cleaning. I took some rubbing alcohol to it and very carefully cleaned it off with some q-tips, and now all is back to normal. No more Restricted Performance or check engine light on in my gauge cluster. Big big smile