Extreme speed and ping issues

I've been having problems with my internet connections stability for the last month. Its been happening extremely often where my internet will drop from its usual max speed to as low as 0.1 mbs. My ping goes through the roof too. Even pinging google while these upstarts are happening ranges from 1000 to 5000 ms. I'm more or less clueless about this sort of thing, but I was wondering if anyone had an idea where to start looking for solutions. Is it more likely to be my ISP or my router?

you might be throttled. do you ever pirate or even have a torrent or visit the pirate bay? because that might be it 

I download and upload existing torrents fairly regularly. I've been torrenting for far longer than this problem has existed though. It's only popped up in the last month, and I've been with my current ISP for years.

Could be ISP issues (line work or bad hops), has your ISP recently changed any user agreements like caps for data or anything along those lines, usually its written is something called a fair usage policy, even if your on an unlimited package your still effected by what they determine as "fair data allowance", i used to be on an unlimited package adsl but its fair usage was 150 gig per month, i didnt have to pay anything if i went over that limit but i spent the next month being throttled at peak times or during heavy usage.

Should also check to see if theres any work being carried out on lines etc along with your own settings, if you using wireless changing the signal channel can help, when someone gets a new electronic appliance these things can interfere with wireless signals so maybe a new washing machine,microwave,hoover,fridge somewhere near could be the cause along with neighbor wireless devices.

If you can safely rule out your setup and any devices near by you should call your ISP and explain the issue, it could be something really simple on their end that they can fix.