Got my first codes tonight. Check engine light and restricted engine performance. I new it was going to happen. Car was running a little rough at highway speeds. I was trying to run without the trac on to see if that made any difference.

p0175 Bank 2 Rich
p0172 Bank 1 Rich
p1111
p1637
p1000

I am leaning towards the MAF sensor. I have cleaned it twice. First time it was very dirty. Does this cause a MAF to go bad? It is a 2000 XJ8 VDP with 67K. Can the MAF sensor go bad this early?

I cleared the code and drove home without the light coming on again. Any help would be appreciated.

 

The troubleshooting guide for code P0175 says:

Engine misfire
Blocked air filter
Fuel system return blockage
Leaking fuel injector(s)
Fuel pressure regulator failure (high fuel pressure)
ECM receiving incorrect signal from one or more of the following sensors - ECT, EOT, FTP, MAF, IAT, TP, IAT2

Code P1637 is a communications error fault on the CAN network
P1000 & P1111 are system flags for incomplete and complete read of system status, you can ignore them for the most part. You always get one or the other.

Based on the fact that you've been messing with the MAF, I'd agree it's a likley canidate.

 

Bought MAF today-OUCH

Will post back results. Will replace plugs as well in case they are fouled by the rick running conition.

 

When I got 0172 and 0175 together, the problem was the vacuum line to the fuel pressure regulator. It had developed a kink that allowed boost (mine is supercharged) but closed off when vacuum was applied.

Acceleration -> boost -> high fuel pressure
Let off throttle -> kinked vacuum line -> continued high fuel pressure -> rich codes when ecu can't compensate with smaller pulse widths

Luckily mine was an easy fix, 12 inches of vacuum tube and problem solved.

TTYL
David

 

on the xj8 the pressure regulator vacuum line does get hard and can give you the rich codes.. maf sensor is very rare to cause a rich running condition.. lately we've been seeing cats falling.. causing rich or lean codes..

 

Put on new MAF sensor this weekend-did not solve the problem. I am going to try plugs next. Haven't got a code anymore since I cleared the original ones.

 

Finally sorted my slight miss/hesitation problem. This forum was a great help to me. Thanks to all the posters. It was a faulty thermostat. I believe that my car was running cold. Whenever I would get the rich codes, I also got a low reading on the temp gage. I changed the thermostat this past weekend, temp gauge exactly where you would expect it to be and the hesitation is gone. I also reset the long term and short term fuel levels by doing the battery reboot. Hope this is a long term fix. Car is running great-knock on wood. Easy to do if you drive a Vanden Plas. Many Thanks.