Hello, everyone! This is my first post asking for advise, so I hope I'm doing it correctly. My check engine light is on and I am getting error codes P0174 and P0171. Does anyone have an idea of where I should start?
James
2004 Jaguar X-Type 3.0l awd

 

The code numbers indicate a lean combustion on the right and left bank. The usual cause is a vacuum leak downstream of the MAF sensor.
The usual suspect are:
1. The brake booster line. It runs from the back of the intake manifold to the brake booster. There is a football shaped check valve about halfway that cracks and leaks.
2. The crankcase vent hose that runs from the front cam cover to the throttle body. The PCV hose has a tendency to crack on the bottom and cause a leak. If the existing hose is smooth then replace it with the updated RIBBED version.
3. The IMT Valve O-rings are also known to leak. They are the 2 round black discs at the passenger side end of the intake manifold.
4. Lastly check the intake plastic piping front the air cleaner to the throttle body for cracks.

If after checking these areas and you haven't located the problem, check back in and we can start looking at more areas to check.

 

 

Thank you, Vern,for the information. I'll check the hose first thing tomorrow after work, as that seems the easiest fix.
James
2994 Jaguar X-Type 3.0l awd