I'll apologise in advance that my mechanic talk only goes so far as "thingy" and "greasy pipe bit". If you guys want to enlighten me on the actually names of any of these bits so that I can at least pretend not to be such a noob I'd be grateful

My baby has been having a bit of trouble.

This pipe that I've marked below keeps coming off!!


First time I noticed was when I took her in for a pinkslip. The mechanic pointed it out and asked if she'd been losing power (all I'd noticed was that she would jump sometimes when accelerating). He reattached the pipe and all was well.
That is until, I'm out on the freeway and she starts losing power when accelerating. I coaxed her home and checked under the bonnet and sure enough the pipe is off again!

Now what could be causing the pipe to blow off??
Is it just a case of replacing the clip because its not holding well enough?
or is this likely to be a symptom of something more serious, a build up of pressure prehaps?

*chewing nails in anticipation*
R