Trouble moving from pinky to 2nd finger

[Rhastapopolus]

Hi guys,

I have recently advanced into playing some pretty demanding bass lines (i.e. some Jaco stuff), and have realized that I have a really hard time using my pinky in a certain way: some of the lines I'm playing require me to fret with my 2nd finger, move to my pinky on the same string, and then MOVE BACK to fretting with the other finger. So essentially this type of line would look like 7-9-7 on the A-string. I have a difficult time executing these lines precisely, as I find my 2nd finger is out of place when I need to move back to it.

I think the root of my issue is that I have the bad habit of picking up my 2nd finger when I fret with my pinky, so that it is not pressed down when I need to move back to it.

So does anybody have an exercise to help develop finger economy in this way, to encourage my 2nd finger to stay in place when I'm playing with my pinky?

Thanks a lot!