hi, any help with this would be much appreciated. the car is a 2000 xj8 executive 3.2.
whilst driving home tonight the engine management light illuminated and the message "reduced power" flashed up on the speedo display for a few seconds then went out but the engine management light stayed on.
i didn't feel any loss of power ( i was travelling at 65mph at the time) and after plugging it in to a diagnostic machine the codes p0171 and p0174 were shown refering to the following two faults:-- "stored":- "system too lean, bank one" and "pending" :-"system too lean bank two". does anyone know what may be at fault to attain these readings or could it be a faulty sensor and if so which sensor is it likely to be? many many thanks in advance for any advice. all the best, rod.

 

Vacuum leak at full load breather hose or air duct to throttle body: inspect the convoluted (bellows) part carefully. Dirty mass air flow sensor, of failing mass air flow sensor. That's the common items to check for the codes you retrieved.

 

hi, my word that was quick and thank you very much for the info i'll get on it this weekend. cheers, rod.

 

Cheers, glad I stopped in at the right time. Look for CRC brand MAFS cleaner. Electrical contact cleaner will suffice, and there are previous posts here about cleaning the mass air flow sensor.

 

My 2001 Jaguar XKR has been occasionally flashing a restricted performance message usually at speeds around 65mph. The amber check engine light stays on. the codes I am getting are p0171,p0174 Bank one and bank two are running lean. I have cleaned the MAF with spray cleaner and will be checking the intake billows and connectors for vacuum leaks next. Were you able to solve your problem? Has anyone else had a similar problem?

 

Most of us have had this problem at one time or another and it's normally something simple like a dirty maf sensor or a small crack in the air ducting somewhere. The stubby breather tube tends to crack if it is not removed when changing the air filter.

 

rod, I concur with all advice above. I had this same problem recently. Check your inlet air duct with a good flashlight in a dark room. I replaced air filter, cleaned MAF sensor as recommended, throttle body, and also replaced fuel filter for ****s and grins (my kid runs around on vapors), it was fixed. If you go after the filter, be sure to get the 2 o-rings needed, one for each end of fuel line. Who knows which item actually cleared up my problem. There are plenty of posts. These Guys are great!

Ralph