I noticed my temp gauge will rise and fall as I'm driving. It'll move up the gauge a small bit, about the width of the needle, then it'll fall back to the middle of the gauge, then back up and on and on.. Should I be concerned? I just bought the car and I reeeally don't want to have a headgasket going on me already. There's doesn't appear to be any oil in the coolant, no coolant in the oil, no steam in the exhaust and the plugs are clean. No problem with heat from the heater. Maybe a bad pressure cap? I've got my fingers crossed that it's not a big problem..

If it's only going up a single mark.... you have NOTHING to worry about at all. Totally normal.... even to go up and down 2 or 3 notches is fine. If it's going to the top of the gauge.... you have issues.

Oh thank god, that's a relief. Still though I'm going to watch the cooling system like a hawk.

And I think I'll replace the pressure cap and thermostat when I get paid again.