Out of the blue, my S60R started to hiccup when shifting into 2nd gear. It's hard not to notice if you're picking up speed, but if you are going slow, the symptom is almost invisible. I say invisible, but it's still there.
It only happens at the 2nd gear shift.

Northern California has recently had many cold freezing nights, which is the only external source I can think of that would cause a malfunction. My 95 '850 always seemed to need a new fuel relay after cold weather.

Is the computer telling me something about this 2nd shift issue? Can I diagnose and repair this myself?

Thanks for reading.