Recently my Jaguar S-Type showed the "restricted performance" indication. Also the engine indication turned on. I ran diagnostics and my OBD device read the following codes: P0171 & P0174 (Car Too Lean).

The funny is that when I put super benzin the problem disappears. The problem seems to occur when I put 95 unleaded.

Anyone who happens to know the causes and -maybe- the solution to this problem?

 

How's the consumption?
It could be an air leak, knowing that it's very easy to get one on the s type. Check everything from the air box to the plastic manifold.
Bad injectors, maybe you need to bench test them and clean them.
Bad fuel pump if the injectors are fine

Also you could try to change your gas station, and try another 95 unleaded

What's your engine year and mileage? And which country?

 

@JaggieJag, what is the MY of the vehicle and which engine is fitted? What work has recently been performed on the engine?

Use a smartphone to connect with the vehicle PCM via the OBD port with a Bluetooth adapter and the Torque app to determine the STFTs and LTFTs.

Under not circumstances is the vehicle to be operated under conditions that cause the MIL to flash as catalyst damage is occurring.

 

It's a 2004 S-Type X200 3.0 (V6).

 

An authorised mechanic told me there is no problem to drive the vehicle. Based on what you say, I think he wasn't right...

 

The chances are this is down to an intake air leak between the MAF sensor and the engine.
But it could be an exhaust leak before the cat.
It will be hard to find as it will only be tiny.
Mellow

 

Thanks for replying, Mellow. I will have a Jag-authorised mechanic to check my car. There aren't many in Greece... Hope he finds out what the problem is...

 

Give a careful eye to the air box, underneath, specifically. Some have reported damage there that thwarted all their previous attempts to find a leak.