What would a broken/out of spec valve sound like...308?

In the last couple of short drives in the 308 there's been an (irregular) off idle flat spot/stumble until I get over 2K RPM.

Pulled into the garage tonight and gave a listen while at idle... I can pick up a regular little tick seemingly under the front cam cover close to the dizzy, which I don't really recall hearing before. When I can hear the tick the engine at idle seems a little flat overall. When the tick dissappears for a quick second the car seems back in tune and up a couple RPM.

I'm going to throw some new plugs in a see if that helps. This summer has been filled with a lot of short little trips which means I could have easily fouled one.

But what concerns me is the tick and the change in engine note when it's either there or gone. Anyway, could a valve be snapped/out of spec/going bad/already floating around and cause an this sort of stumble and "flat" note?

BTW, 1980 308

Thanks

 

Perhaps a plug wire, extention or plug is on the fritz?

The overall sound feel of the stumble is that of a fouled/bad plug... it would be nice if that were the case!

 

I've had a box of new red wires just waiting to be swicthed into the car. Sounds like now is a good time to tackle that project.

Thank you! And let's hope it just that simple.