Process of elimination. All the vacuum lines start at the intake manifold - There's usually a 1/4" fitting on the manifold with a tube running to a splitter manifold. To make sure the diagnosis is correct, pull the main line & temporarily seal the intake manifold fitting & see if it smooths the idle out. If so, then just start with each hose running off the splitter manifold, until you find the one that stops the surging. Just make sure you seal the opened line. After you find the problem line, move up that line unhooking the line at each end & sealing the vacuum side, until you find the fault.

At that level of leak it ought to be found fairly easily .

With engine running use starting spray or cigar smoke. Carefully blow around vacuum lines and joints . If nothing ducked in? Or noticeable sudden change in revs? Indicating potential leak spot.

Then do again and move all parts of lines where possible so as to maximise ant pinhole.

Look on utube for tips ..how to...locate vacuum leaks video etc.

Rubber hose is cheap . You could just start replacing vacuum hoses and hope you get lucky .

The plus is that you'd have all new lines .

You don't fix it you replace the line, not that hard any competent spanner monkey can do it.

I drive a 1998 Camry I took it to the mechanics and they told me there's a leak in the vacuum line. Only problem is that they said it's so small at the moment they're unable to pinpoint. Any tips on how I could possibly find it myself and fix it? It's constantly idling rough and shutting off now it's not a comfortable feeling having to drive it.

Thanks for any help