I had one of our vehicles in the shop recently, and they worked on a rough idle problem. When I got the car back, I found that one of the things they did was take a big-gauge piece of hose and clamp it around the PCV valve. In other words, the PCV valve is now like this:
X-------X input ===X= PCV =X=== output X-------X
where XXX are hose clamps and --- shows the walls of the new piece of hose.
Presumably this is to work around a leak. But what is this doing to the car? It passed emissions testing, but is this modification legal? Why did they not simply replace the PCV and/or the hoses that lead to it, if they're leaky? (It's my money...)