Hey everyone I'm very new to this forum but it seems like the best place to go to help troubleshoot my car. I just purchased a 2005 3.0L jaguar x-type from a private sale that seems to have some kind of fuel issue. but I can't diagnose it. When going highway speeds and the engine starts to warm up the car surges and rocks back and forth. and after reaching those speeds and warming up it begins surging during heavy acceleration (like getting up to speed after a red light). I put a code reader in and got a P0191 code so I went to check out the IP sensor (AKA fuel rail pressure sensor) and discovered that the vacuum line running from that sensor was spilt in half. so i gave it a solid but temporary fix to see if it was the issue and took it back on the road only to find it still surges so now I'm confused and need others help. I probed the wiring harness to the IP sensor and it's getting 5 volts like it should be and you can hear the fuel pump priming when you start the car so its probably not the pump. It could still be the IP sensor, or maybe the fuel pressure regulator, or the fuel filter, or the MAF sensor, or the throttle body. If any of you have had a similar experience with your jaguar can you guys share how you fixed it or if you have any idea how I can get mine back out on the road safely it would be greatly appreciated

 

Has the car self-cleared the code?

If not, when you have done at least 2 warm ups do you have P1111 or P1000?

 

Use a smart phone to connect to the vehicle PCM via the OBD port with a Bluetooth adapter and the Torque app to read fuel pressure and LTFTs and STFTs.

Does the MIL flash during acceleration?

 

The check engine light went away but the P0191 code is still there. there isnt a P1111 code but there is a P1000 code pending.

 

My code reader isn't that sophisticated and no the MIL doesn't flash but it did turn on. However, It went away once I repaired the vacuum hose

 

So long as you didn't clear the codes, MIL off means the car is (fairly) happy and the fault has stayed away for several warm ups. The actual code is kept for a while to allow diagnosis (and can be ignored).

If you cleared the codes and yet have a code then the fault is still there and you can expect the MIL on shortly.

You want P1111 but it can take a few drives / specific conditions.