some sanity checks:
1. when you say lube the outer cable do you mean putting grease or oil in the cable housing (approx 1/8" thick, hollow).
2. make sure the rear drop out is tight - when you remove the rear wheel you'll see a screw holding it on.
3. make sure the cable is clamped on the correct side of the anchor bolt.
4. lube the rear derailleur thoroughly so that it freely moves through its range of motion.
5. lube the shifter thoroughly as well. if you look at a diagram of the shifter, lube the thing the cable wraps around, not the pivots for the braking part of the brake lever.
If the derailleur is clicking in one end of the gears but not the other, then either the derailleur and shifter are not compatible or the derailleur is a bit bent. Manually moving the derailleur and getting all the gears indicates the limit screws should be okay (else you wouldn't get into the small or large cogs). The clicking indicates that the derailleur is moving a different amount sideways than the shifter wants it to move.
some more detailed checks:
1a. from behind, pull down on the rear der cage until it is vertical (so the two pulleys are vertical anyway). usually derailleurs get bent inward. if you notice more than about a half of this tilt --> / then grab the lower cage and gently but firmly flex it outward about 1/2". it should pop back about 2-3 mm (1/16"?) more vertical.
1b. in the small small combination (for example, 39x12), the rear derailleur cage should be almost horizontal. does it point straight fore/aft or is it noticeably skewed one way? try tweaking it the other direction.
2. when in the smallest cog (all the way to the right), wiggle the rear der. It may be loose, i.e. there is play in the various pivots. If there is play you may need to replace the derailleur. (the same test applies for the front derailleur). one of the unseen but expensive features of a derailleur is the quality of the pivots. Less expensive derailleurs of all makes have inexpensive, cheap, and short lived pivots. expensive derailleurs have much stronger pivots and last a lot longer.
3. are the clicks in the shifter solid? are they similar from the left shifter to the right one? if they feel different (and the right side is softer as it usually is) then you may need to replace the springs in the ergo lever. worst case is the gear wheel itself is worn/chipped. neither is a major deal but it involves removing the lever in question. this means retaping the handlebar and removing the shift cable (which if it's frayed at the end means replacing it). 1 hour for the first time you do it, 30 minutes from then on.
hope this helps
