Jaguar Repair Problems? Ask a Jaguar Repairs Expert.
Hello, my name is ***** ***** I am a professional here at Just Answer. I have noticed that your question was not getting a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.In order to determine what is failing with the cruise control signal you are going to need to start first with scanning the system to see what the fault code and or codes are that should be setting . Once you have them then the pinpoint test for that code can be performed. If you can get the scan done and post back with the fault code I will help you from there.
The lean code P0171 and P0174 on your 3.0 are common to set due to leaking Intake Manifold Tuning Valve O-Rings and its very common for them to leak . I would start first with Replacing the Intake Manifold Tuning o-rings, upper and lower. These code will have no affect on the cruise control which is a separate issue. Let get these codes addressed first.
I agrre with you , Lets get the vacuum leaks corrected and see if this will resolve the problem your having with the cruise control . Im here if you need me. Let me know.