Another Cooling Problem

This is what happens: When I first start driving the car, it heats up normally. After a little while (about 2 miles), the temp climbs way up, up into the A and L area, but so far the car hasn't gotten out of normal. But after a while of driving, it'll drop back down into the R and M area. Sometimes it goes back up under acceleration (any accel, period) but will drop back down while cruising.

I've got a leak somewhere, I'm fairly sure, but I haven't pressure checked, yet, so I'll do that first. But does anyone know anything specific that could cause a weird cooling problem like that? Time of day doesn't change much, either. It's only slightly cooler when driving at night than it is driving in the afternoon. Not even a half-letter difference but enough to be noticeable.

Also, anyone know an easy way to get this damn upper radiator hose off?

Yeah, my dad said I should bleed it after i flush/seal it. I'm pretty sure the temp sensor is good. I've never bled a cooling system before, how would I go about doing it?

Hmm, but I don't have a compressor, so that way is pretty much out. I think I have it worked out, though, because I was putting in some flush, ran the car until it heated up, squeezes the upper hose a few times and suddenly the contents of the overflow bottle was sucked into the radiator.