Jaguar Repair: POOR GAS Millage, vacuum leaks, vacuum leak

Question
Sam you did aswer my first question. its a 87 XJ6 4.2. I checked the air filter. Replaced dist.cap rotor Ichecked for vacuum leaks. & replace spark plug wires.two questions.if a car starts & idles fine when its warm. am i correct that if their were a vacuum leak it  would not idle & start well. next question when i pulled the plugs they show no signs of
gas or oil im thinking that the plugs are to clean to be burning excessive gas am i correct. on my thinking if so now what.i still have a pore gas milage problem Please advise
  THANKS Howard

Answer
 You are on the right track. Now you need to put some fuel injector cleaner in your gas tank.
You may have to try a few different types to do the job. I was given some injector cleaner once by a product salesman and my gas mileage went from about 13 MPG to over 18 MPG. I really saw a big change in gas mileage. So please have your injectors cleaned or try a few different type of cleaners. Sam