Ossilating subs

Ok I posted on here before about how to get more spl out of my system and rob helped out quite a bit. So I made a wall with sliding square ports so I could change the box from spl to everday listing (well as everyday as you can get with a wall). So I got everthing installed and I turned the system on and the subs sit there and ossilate. Not a lot but I want perfect not almost perfect. I have the following gear,

4-12 Pioneer 305DVC

Alpine Head Unit (cant remember model number right now)

Audio Control 3.1 Pre-amp

Pioneer Rev 61/2s in kick pods

Orion HCCA 425 to the subs

2-MTX RT-01 crossovers

1faurd Stinger Cap

Ok so the cap is grounded seperatly from everything else, the amps and trunk mount crossovers are all grounded to a distribution block which then goes to chassis. The power for the amp, cap, crossovers all go through a second distribution block. The 3.1 and the deck have their own grounds up at the front of the vehicle as well as seperate power wires from the fuse box. The remote line has a relay in line and all the grounds on the car have been redone with larger wire to match the system. The only thing I can think of is that the amp ground is a little long, like 3 1/2 to 4 feet but I cant get it closer due to the install, its just not possible. My power wire and the remote run down the opposite side of the car from the RCA's. This is all in  a 1994 Swift. I am sure this is not a big problem but I cant figure it out.

Oscillation - n

(1) an octopus that has flailing arms

(2)  an out of control wet fart

(3) a Sony on a good day

(4) a rythmic motion of the cone

1. To swing back and forth with a steady, uninterrupted rhythm.
2. To waver, as between conflicting opinions or courses of action; vacillate: "The court has oscillated over the decades from more liberal to less, more conservative to less, depending upon who was president at the time of vacancies" (Gordon J. Humphrey). See Synonyms at swing.
3. Physics To vary between alternate extremes, usually within a definable period of time.

I'm not sure what you mean by "5%" or "10%"...

As far as the RCA's go, the problem might be that the ground (or shield as it is called) on the outer ring of the cable is bad.  This can cause a ground loop and make the speakers 'pump" like you describe.  So when I said intact I did not mean plugged in.  If you can, try running a new RCA cable, even if it is just draped over the seats temporarily to see if that is the problem. 

Also, the Orion is a 4-channel amp.  Are you running seperate channels to each sub?  The Orion is a great amp, but it is an older model and may not be able to handle the 13 volt peak output from the AC Three.1, so no matter how low your amp gain is set you could still be over-driving it.  Try removing the Three.1 from the signal chain and see if the oscillation stops.  If so, the amp can't handle the voltage.