[Corsa D] Corsa 1.2 (63 plate) juddering at idle, lights flicker and ticking noise from enginer

[Jazzhands]

Hi all, hoping someone can help me.

I bought my son a used 63 plate Corsa 1.2 LE. Sod's law, two weeks out of warranty and it has decided to play up. Symptoms are that when idling and up to around 1400 RPM there is a judder from the engine, the rev counter seems to dip slightly and the headlights/interior lights dim slightly in unison with the judder. Listening under the bonnet there is a definite ticking sound too coming from the rear side of the engine (nearest to cockpit) which sounds like an electrical connection.

Before I go down the expensive route of taking it back to the Vauxhall dealer, has anyone got any pointers of things I can check or change?

[Restorer]

Could be the alternator . Check what voltage you've got at the battery. Across the terminals with a multimeter, should be about 14.2 volts. At idle. Check the wiring loom that runs across the gearbox at the back .it could of rubbed through. If you think something is arching out on the engine, best time to look for it is in the dark.

[Jazzhands]

Thanks Restorer. Just to close out, turned out to be the Coil Pack and plugs in the end. Changed and all good now.