I have a 87 jag xj6, and I suspect a theres a vaccum leak. What is the most efficient way to fond a vaccum leak??

Bob

 

Modern practice is to carry out a smoke test.
https://roadsumo.com/smoke-test-car/
I've never had one done, or even seen one done, but there was a YouTube video some months ago by the Car Wizard on this technique.

 

get a Habana cigar, light it, take a big puff and blow it into any vacuum line. Keep blowing and smoke will come out where the leak is. Do this with engine OFF. Enjoy the cigar.

 

I smoked cigars for 15 years, but quit 4 years ago. I've been looking for an excuse to light up, and you just gave it to me
Thanks !!
Bob

 

 

Long fuel hose on a Burns o Matic. I take the jet out of mine. Cracking the valve slowly near gaskets and hoses - listen for a RPM increase.

 

Same suggestion as above, but use "Easy Start" (Ether).

 

Problem with ether and carb cleaner is to volatile. They head to the intake and fool you in the diagnosis. Propane is heavy & drops. Lessens the chance of miss diagnosis. The valve on the burnz a matic. Let's you dispense small amounts when you are looking for a change in rpm. If the system is already too rich - rpm goes down. Lean - rpm goes up.