exaust flames

[Zman]

I'm almost ashamed of posting this, don't want to be seen as rice boy or anything.

Here it goes.

I want to wire in a spark plug in the exaust pipe, to my defense this is done on my "to have fun with" car.

So far I have understood that I need to wire in a coil. This is not a problem. The problem is that if the coil is connected it will give a spark when first connected and that's it.

So I need some kind of automatic switch that opens and closes the cirucuit.
Has anyone tryed connecting something like this before?