Thanks for reading.

I have an '03 XJ8, and I am getting a P0174 (and p1111 as usual), but I am NOT getting the the P0171 that most people seem to get alongside p0174

Originally, I had a P0174 and P0171, which I read was either associated with a cracked air line or a dirty MAF sensor, so I removed the entire accordion air tube (which connects the throttle body to the filter), thoroughly inspected it for cracks, and cleaned the MAF with CRC contact cleaner. I noticed that the "sound attenuator" (the bit of plastic that sticks out of the main tube and appears to go nowhere) had been cracked as though snapped back partially, so I wrapped some tape around it and sealed.

Once I put everything back together, and cleaned and lubricated my contacts with contact lube, the P0171 had gone away but the P0174 remained. I tried the hillbilly mechanic trick of using a bit of ether/starting fluid to look for a vacuum leak (if you spray ether near the leak, it should cause the engine to rev up briefly due to the ether mixing with the intake air). No luck finding a leak.

Any guesses as to what the issue might be? High on my list at this point would to be inspect my fuel supply, specifically changing my filter, but I am not sure about this.

Thanks again for reading.
-Rich

 

Well, I had the P0171 and P0174 and it was a cracked part load breather hose. You could check that and the full load breather hose on the RH side. P0174 is RH side - Bank 2, right ? It sure sounds like a vacuum leak, but changing the fuel filter might help. It won't hurt anyway.

 

Yes, check for vacuum leaks first. The part load breather (the small tube going into the driver's cam cover) is usually brittle from age and heat cycles and can crack. The other side is the full load breather that goes into the passenger's cam cover by the air filter. One test I always did if I couldn't see a leak was to rev the engine and listen carefully for a stumble or slow or not smooth acceleration. I would be careful with this as well. Leave it in park and rev the engine from under the hood. Pay attention to how it sounds. I personally would lean towards a Mass Air Flow sensor failure. I replaced many of these over the years with no further problems.
Good luck

 

After thorughly cleaning the MAF sensor, I am now getting P1647 and P1074. P1674 relates to the O2 sensor... does this make any sense in any context I am gonna need your help in identifying which hose you mean. I checked the large Air hose that goes from the air filter to the throttle body, and that contains the sound resonator (if your car isn't supercharged). if there is another hose, I am not sure what it might be, and need some help IDing it. Could you possibly be referring to the very small hose that attaches TO this larger hose right after the MAF sensor? I tried taking this off and noticed it has some oil in it, not sure if that is normal or not. Thanks, -Rich

 

I did a bit of research and identified the Part Load Breather (which I didnt realize was the actual name of the part)

Lifted the cam cover and lo and behold, the breather hose had been shorn off, and fixed by a previous owner with some duct tape. I am ordering a new hose, but in the mean time I fixed it up with some new tape, cleared codes, and took it out. It is running WAY better.

However, My new code 1647 STILL remains. Is it possible that my O2 sensor exploded completely simultaneously to these other issues?

And as a side note, I want to take a moment and seriously thank you guys. This community is the only reason my car is on the road today.

 

Glad to hear the part load breather was a problem. Duct tape fixes everything, right? I looked and looked in Jaguar's stuff and cannot find the 1647 or the 107x codes you have. I remember seeing them on cars but don't recall what they were. I'm going to have to assume the internet is correct with the oxygen sensor being faulty. I had a Rover in this week that had lean codes and oxygen sensor codes. They all went away after the repair not to return. If you have a good enough scanner, monitor the oxygen sensors. The upstream will be in milliamps and swing around zero (positive and negative side) The downstream will be in volts and should not swing much at all (range is about 0-5 volts) and (a failed cat is found by the downstream sensors moving as much as the upstream sensors). Also, since you cannot reset the adaptions, you'll have to drive it for a while after the final repair on the breather tube. Since it had a lean condition for a long time, the adaptions have recognized. they will have to make their way back to baseline on their own.

Keep on keepin on

 

Its distinctly possible that the still shitty duct tape work and possibly other cracks in the hose that I have yet to find are the cause of all of the continued trouble, so I will report back once I get my part in and get a chance to test

 

My XK8 said lean on one bank after having the transmission rebuilt, less than a block away. The transmission shop said it was a vacuum leak not related to the transmission. I took it to a great mechanic who said it was the upstream oxygen sensor. I ordered a new one and when he went to replace it he found one of the wires pulled out of the plug (probably done by the transmission shop). He put it back in and I have not had a problem in over a year. I still have the sensor...

I just had a lean on both banks on my XJ8 and it was the Mass Air Flow sensor. I got a remanufactured one at O' Reiley's for $69.99 and it took 5 minutes to replace and reset the computer.