I noticed my tensioner jerks when the car is idling. Here'* a video to show you what it'* doing.

http://media.putfile.com/Tensioner

The camera jerked pretty hard.

That tensioner is pretty normal. Doesn't seem to be causing any slippage?

Here'* a better one. Ignore my stupid cousins (you can hear them.)

Here it is - http://media.putfile.com/Bjetter

Nothing I see there worries me. If you put a ratchet on it as if you are removing the belt...it should be a consistant pull when removing tension from the belt and it should return to tensioning the belt each time you let it go. Try this about 4-5 times.

I just did that. It must be ok. THe wrench slipped off and the tensioner snapped back. So I seems ok.

Don't get hurt

I'd try it 3-4 times and look for the same result. However..I know that my tensioners do the same slight movements.

Don't get hurt? I have been cut, bruised and scraped exactly 14 times since I had the car.

Stop counting ... wimps do that... post the good cuts and bruises in the lounge

Meanwhile...please double check the tensioner and report back.

I didn't count... It was a joke.

But yup, the tensioner is ok. No slippage, I revved it up quite a bit and had a few neighbor kids come over and look at the engine in awe, and of course, one noticed that it was pink under the hood!

Life plays cruel jokes at times... next time do it with the hood closed...although I fear you are branded in the neighborhood.