I’ve noticed in the passing months that I’m getting a vibration from my engine in my ZJ. It’s audible only and only in first gear and from about 2 1/4 to 3 grand on the tac. Not throwing any codes and hasn’t sense I replaced the o2 sensor last fall. It is due for an oil change soon it’s not causing any problems no misses or rich conditions spark plugs and wires are in new condition I’d just like to know what it could possibly be Incase it gets worse and something happens, or is it just showing it’s quarter of a million miles.