mkc

Precise stitch is usually regulated - stitches happen as you move and you set a stitch length. When you stop the head, the stitching stops; the faster you go, the faster the head stitches in order to keep the stitch length consistent.

Cruise is usually the term for non-regulated mode (where the head keeps stitching at a stitches-per-minute rate). Stitch length in cruise will change if the speed you move the head changes.

In precise stitch (and I'm guessing basting stitch is something like 1/4" stitch length, regulated), if stitches are long and there are no holes where a stitch normally should be, it means the encoders haven't picked up the movement on the head on the rails OR the signal from them hasn't been properly sent to the head OR the user is moving the head too fast for the encoders to keep up.

Since it sounds like the Juki stitches fine in cruise mode, it's quite unlikely for it to be a timing issue.