huge woofer sq problems

I'm running 2 Rockford Fosgate P3s at 2 ohms from a RF P5002 in stereo, and I've started getting some strange things out of my woofers recently.

The second thing has become much more frequent in the alst few days.  My amp will cut power to one sub and it sound like it'll double the power to the remaining one...and won't necessarily revert back to "normal".  I think it might be a bad channel, but when I opened it up I couldn't see any busted or burned sauder. Any ideas besides a new amp? I love the thing and really don't want to part with it. in case it's important - it's the 2005 model with the chrome covers.

The amp was well out warranty when I opened it a few weeks back and didn't change anything, just took a look around.

If I unhook the woofer that works, the "intermittent" woofer stays just the same.  You can feel it move, but only slightly.  If I take the leads from the amp channel that seems to be causing the issues and hook to the intermittent woofer, that woofer behaves like the "loud" woofer.  I guess it's possible the RCAs might be bad.  They're made by RF and they're less than a year old.  They run down my passenger side away from any power wires so that's out of the question.  It seems the woofer is getting a dirty signal from the amp, so I guess the it could be the HU originating it all.  The woofer will move with my HU on pause, and when it's not on pause the woofer moves oddly...like it's still getting the dirty signal but can play the music just fine.  How do you test RCAs?  I guess I could hook them up to my buddy's amp and try it that way, but other than that I have no idea how to test them.