Vw engine 'hunting'

I have a 2003 Boom low with a 1600 fuel injected engine, (i believe) and a weird thing happens when any electrical item is turned on ie lights, or brake lights, the engine 'hunts' the revs go up and then immediately down constantly, and eventually the engine cuts out when on tickover, but will operate ok whilst revving, its almost like the extra load being placed on the alternator, is being over compensated while on tickover, if I hold the revs just off tickover its fine, can any of you good people shed any light on this strange phenomenon.

Welcome to Trike Talk Rich.

It does sound like it's electrical, but hard to diagnose in text. (assuming "tickover" = idle)

If you've not done so, I'd check fuel pressure and wiring to the fuel pump.

Can't be too difficult to pinpoint your problems, after all it's a VW!

Good luck.

Hmmmm... ok

Going by memory and having very little experience with a Boom.

So by memory.....It is an aftermarket type ECU. Much like a megasquirt is here in the USA.

I want to say Triject brand. With a mix of euro Ford and German Bosch parts.

All UCU's are voltage sensitive.

Ok back.....family stuff.

So check for stuff draining power causing a low voltage. Possible the alternator can put out enough to get the voltage up at rpm.

Then check wire connectors and connections. Especially battery post.

Then check for any vacuum leaks. Such as the rubber boots on intake and any rubber tubing going to a MAP sensor.

Thank you all for your good advice, i will investigate all possibilities and try and get to the bottom of it.