Hey guys! So my 03 Jaguar has lean codes both on bank 1 and 2 and right now, the only noticeable thing I can observe is the throttle body sounding like it’s snorting or like ticking kind of. My average mpg is really low at 12mpg and it’s been constant like that for the 2 weeks i’ve had my X-Type. Along with that is it has a rough idle. Any ideas? Really appreciate all the help!

 

Lean codes for both banks is an indication of un-metered air AKA vacuum leak. You need to check the inlet hose from the air cleaner, the gasket for throttle body to manifold and last but not least the PCV hose from the cam cover to the manifold. You have a crack or brake on one of them. The other areas known for vacuum leaks are the brake booster vacuum line attached the back of the manifold and the IMT seals on the right hand side of the manifold.

 

And check your air filter