Today in stop & go while idleing the engine started surging from a rough idle to 1800 or so and back down. Ran well on the road with no issues, and it's not showing any codes.
Internet tells me it could be lean fuel, clogged injectors, vacuum leak and some others none of which seem to connect in my mind.
Any clues or experience for me?

I had surge at idle & I cleaned the MAF sensor. That helped. I also changed the PVC valve & it seemed to help but that could just be a Placebo effect. 1st I would check vacuum hoses for cracks.

Is there any harm in driving it as is until I solve the issue?