6th Gen I4 Accord: Engine RPMs drop too low

I have noticed a few times that, when sticking in the clutch and coasting, the engine speed will drop very low, like to a couple hundred RPM, then bounce back up to 750. I always worried it would stall. Well, the other day she did stall on me. The engine was just beginning to warm up, I was cruising in 5th at 45 or so when I popped in the clutch and the engine died.

Is there any way I can control the RPMs such that it won't do this? It seems like the RPMs just drop too quickly and overshoot the 750 idle speed. I'm not sure if I noticed it before I put on the CAI, but I think it was a problem pre-CAI.

Could there be a slight vacuum problem, or some other cause of it? It's not a big deal, it only happened once and I'm sure it'll be rare, also it's not like I'm driving with the transmission engaged when it happens....it's more of a nuissance.

b