Vaccum line leakage

Properway is to introduce smoke into the system, car not running, & see if it produces anywhere it shouldn't.

Another approach is to take a propane torch, NOT LIT, and pass the nozzle around various hoses and such. A running engine should increase RPM if the hose is pulling in propane vapors.

AJ

You can also use starting fluid. Better yet, on a car that old, why not replace all the vacuum hoses with new? It will take a few hours but will be well worth the trouble. Get a pair of big needle nose pliers, some needle nose visegrips and a few screw drivers to pry the hoses off of their nipples without breaking anything. I think they even make a hose puller tool. Use some silicone lubricant on the nipples before installing the new hoses as it will make installation very easy.

Chris

If you like REAL excitement use the starter fluid. Propane is relatively harmless around spark whereas with starting fluid things go real bad really really fast. The most insignificant source of ignition will light up the can and your new nickname will be "Lefty" if not "Blacky" or "Rest In Peacey". SF is so volatile it ignites under compression - used to boost start diesel trucks on cold days. Stay away from SF. Run the propane around the intake manifold, intakes, MAF, etc. to look for leaks at places other than hose connections.

AJF

Good point, AJ. I did use SF once to find a vacuum leak and it caused the engine knock pretty badly for a moment which told me I had a leak, but I could tell the engine did NOT like it!!! A mechanic told be about using it, but he didn't advise me of said dangers, so I disavow any guilt associated with this technique!

Chris