Hi all, I was wondering if there is a good practical way to check for vacuum leaks on my 96 4.9L. I have a PO171 code for lean exhaust that keeps the check engine light on. Since a lean condition can be the result of a vacuum leak I need to check it.

 

unlit propane torch. When idle shoots up you've found the leak

 

I've heard of but never seen the use of a smoke generator.. sounds like it would work quite well.

You could also try pressurizing the system with air and listen for leaks, or use a vacuum pump to try to establish a vacuum, it would require something quiet so you could listen for leaks obviously, and you'll have to seal the vacuum attachments at the intake.

 

Thanks for the replys. I'm gonna work on it next weekend and I'll post what I find.