****Dammit, my computer logged me out before I could finish my reply and I lost it all. I'll attempt to recreate it****
Okay, I figured I'd mention this because I've noticed the number 2,000 being thrown around a lot, and I think it might be promoting an irrational fear.
People do not need to be afraid of cruising with the tach below 2,000rpm. The only thing they should be wary of is throwing open the throttle at such a low engine speed.
I try to drive efficiency-minded, pardon the cumbersome term. I'll bury the tach needle into the mid 1,000s as quickly as possible when cruising around town. This means that I accelerate gently through all the gears and I'm upshifting at just over 2,000rpm.
The surface roads in my area are predominantly 40mph and sometimes 30mph zones, and I get away with cruising in exclusively 5th gear and 4th gear, respectively (granted, I usually drive 5mph or so above the limit). The moment I need to change speed (either accelerating or decelerating), I drop 2 gears and do my business.
I'm essentially echoing TYSHO's point here; I'm reiterating because I think a lot of people are spending extended periods driving in much jumpier and gas-hungry gears than they need to, out of this fear of 2,000rpm.
Like TYSHO said, you will be able to feel your engine behave differently under different loads and conditions. You will be able to feel when you need to downshift... after a while, you'll know when the shift needs to come and will be able to do so before you even feel it. Avoiding engine lugging, even when cruising at low rpms as often as I do, is quite easy.
