But work fine today.

How's that for strange?

Yesterday was the first time I've ever noticed any spiking in the pedals of my MOMO Black. The brake started staying on a little bit even when I was fully off of it. The throttle input was erratic. This is obviously unacceptable in a racing environment, which led me to believe the pedals were shot and I couldn't drive LFS until I got new ones.

I gave it another try this afternoon and both pedal inputs are nice and smooth. Any reason why this might have occured? Is it a sign they might be on their way out? Is there anything I can do to prevent it? Or anything I can do to fix them permanently if (once) they do eventually fail?

It´s a common problem with momo. Take a look at this pictures. It will prevent that the pots moves. That maybe causes the spiking.
And here you got a guide to reapair them

You are not the only one having this issue, I have it too. My gas pedal doesn't spike, but my brake pedal does stay on sometimes even if I'm not pressing it. The problem for me is the pedals connector which plugs into the wheel. I have to bend the cable a certain way to get the wheel to recognize the pedals. I suppose the momo does not have a very rugged design. Anyway, I workaround this issue. If I find the brake is pressed down, I unplug the USB cable from the computer then plug it back in, and the wheel resets itself. This fixes all the issues. I hope it does so for you too.

NitroNitrous, it's not always that problem, for me its a wiring problem, and there really is no way to fix that, other than replace all the wires!

black momos tend to have a lot of issues, especially with the pedals.

as mine started spiking extremely i just opened them and cleaned the whole area a bit. they´ve been working from then on without any bigger problems.
although they start spiking again :/

forgot to mention: my gas pedal never really worked anymore. when i fully pressed it down i had a lot of spikes, not full throttle. solved that problem with not pushing the pedal to the floor when calibrating and checking the fixed calibration option. it´s less sensitive of course, but it works.

Funny how you run wr's without a working gas pedal . Now that's skill!