I'm guessing that I ahve a vacum leak somewhere on the intake side that's causing my rough idle when I'm warmed up.

So what's the best way to locate the leak? I've heard about using some tubing as a stethoscope kinda thingy, I haven't had much success with this, could I just be doing it wrong. The other way I've heard about is using a flamable spray, it gets sucked into the leak, and RPMs jump, I haven't tried this yet, anyone tried it, any advice about what kind of spray to use?

Thanks for your help

 

My '91 N/A is suffering from the same symptoms, and I want to eliminate the possibility a vacuum leak in the brake booster (probably don't want flammable fluids in there).

Also want to check the intake system, I have heard that WD40 makes a good engine cleaner...(two jobs at once?).

What's best for each area?

 

WD-40 for intake leaks works well.

The brake booster leak.....no idea on that one .