So as the title says. Engine vibration both at idle and around 1600RPM has been getting worse recently. Progressively for the last year. I've noticed when my alternator engages (as seen by my battery voltage jumping from 12.8v to 14.3v on obd) the idle hunts and engine vibration and clatter increases notably. If the AC is then engaged, the hunting, clatter and vibration increase again, with the tacho rhythmically going up and down and the car thrumming in time with it. I can feel vibration through the gearstick when I move it side to side. The engine makes an ungodly clatter under load around 1500-1700rpm. I can't tell if I'm just being paranoid but the throttle response feels much laggier than it did last year

I've replaced: idler pulley, deflector pulley, tensioner (put an aftermarket one on, then put the OEM one back on as the aftermarket one bounced constantly). Had a new alternator about 6 months ago. 

I'm going to monitor the p4int marks on the crankshaft pulley over time to see if they slip. I asked chatgpt and it pointed out the rubber ring on my pulley is starting to crack and age visibly, and said this is DEFINITELY THE ISSUE NEW CRANKSHAFT PULLLEY NOWWW!! I'm not convinced though. Human opinions pls!

Kia Sportage 1.7 diesel 2013. Manual trans

Trying to diagnose my idle hunting, noisy aux system under load.