Afternoon everybody.

My wifes '02 XJR has Codes P0171/P0174 and the check engine light is on and when I get on the gas hard I get the restricted performance call out on the dash.

I have searched and searched for possible vacuum leakes but have found none.

I just cleaned the Mass Air Flow Sensor as this has been a problem on this car in the past.

After cleaning the MAF sensor I could really get into the gas and did not get the restricted performance call out, but I still have the check engine light. I have not cleared the codes yet since I cleaned the MAF during lunch and didn't have my code scanner with me.

Does it make sense that it could be the MAF sensor? If it was just dirty, how do I prevent this from happening in the future, or should I just make it part of my regular maintenance to pull it and clean it?

 

You may find this link useful, there are many posts regarding lean fueling but this sums it up :

P0174 Jaguar System Too Lean Bank 2 OBDII Engine Light Trouble Code | Engine-Codes.com

Quoting from here :

"If the P0171 is combined with the P0174 code, it's very likely that the problem is caused by an intake leak. If there are no intake leaks, the next step is to replace the air filter and clean the air flow meter. If the problem persist the front oxygen (O2) sensor may need to be replaced."

Hope you solve it !

AndyP

 

Andy, Thanks for the link. I haven't changed the air filter yet, but will this weekend.

After cleaning the MAF sensor, I was able to get into the gas really hard without the reduced performance call out on the dash showing up.

I cleared the engine codes and the check engine light went out. I took it out for a short test drive and was able to take it from zero to triple digits with the accelerator to the floor. It accelerated very strongly and did not throw any codes.

Thanks everybody for keeping this forum so active. I have never not gotten some help or ideas to check. Time and time again.

I'm sure I'll be back since I own a Jag.

 

See if this helps you with your problem

Link http://www.jagrepair.com/images/Auto..._2001_OBD2.pdf

Link http://www.jagrepair.com/images/Auto...otos/P0171.pdf

 

Thanks Gus.