Bad packet loss

Here's additional screenshots:

Pingtest - http://imgur.com/MIwhpJv

Speedtest from google's page - http://imgur.com/9DpNmL3 (note: I've got the 150 down package, so this is just sad)

Tracert's to Google.com - http://imgur.com/V58CkEY

Let's take a look at these -

http://imgur.com/yFa356E

This shows that you power-cycled your modem at approx 18:37 on Dec 16th, and last had an issue on Dec 14th (approx 11:15am).  You also had some issues at or around Dec 13th ~15:00 -> 17:00

http://imgur.com/PkXsxgs

Shows a perfectly acceptable signal range for an SB6141 modem (4 up 8 down, surfboard status page)

Reception: Signal to noise > 35 dB  Power Levels between -4 and -3 dBmV

Transmission: Powerlevels in the 40-45 dBmV range

Error Correction: negligable except on channel 34 (867MHz) with an error rate (correctable) of 0.043%  - This can usually be corrected by powercycling the modem several times so that it chooses a better channel.

Pingtest shows the standard issue of Java/Adobe Flash (IE it couldn't check it) - although your pings are high with high jitter.

Traceroute unfortunately doesn't really reveal that much, other than the route seems to be under heavy load, which could be related to your pings.

Okay so troubleshooting steps:

Question 1: Are you testing over a wired or wireless connection?

Question 1a: If you are on wireless are you testing on the 2.4Ghz or the 5Ghz band?

Question 2: Since this looks like a SB6141 modem, and your tracert suggests an Asus RT-68 router, can you confirm these deductions?  Are you using stock up-to-date firmware, Merlin's AsusWRT, or a different fork?

Question 3: Is there a way of bypassing your router?  It is suspicious that several pings responses from your modem failed, and the modem is reporting responses varying from 8ms to 26ms on just that hop, which is typical for congested wifi environments.

Plugged into modem directly, still no better. I did a few more resets/recycles - no improvement.

Two of the upload channels showed a ranging status of "Aborted" (didnt get a screenshot)

I left it alone. I noticed it dropped out entirely on it's own for a bit, and took a long time to come back up.  

When I checked the logs, I saw a "cable modem reboot due to a T4 timeout".

Then the modem rebooted again on its own shortly after.

Now everything seems to be okay. Speeds arent quite what I should be getting (getting in the 50s as opposed to 150 like normal), but stability is here.

Current state:

http://imgur.com/bQwN6MN

http://imgur.com/XfEDjSh 

Honestly if you started to have such issues after switching what was plugged into the modem, I'd check the coax lines, reseat them and make sure they are finger tight.  It is typical with a bad connection/loose connector for issues to appear when moving the modem itself.  It could be any number of things, but checking the coax at the wall and going to the modem is never a bad idea.