Since about 3 weeks ago my DSL has been getting totally random ping spikes, from under 40 to over 1500MS for minutes to hours on end. Nobody else is using my internet, I've verified this. There is nothing sucking up bandwidth on any connected device or computer, as far as I can tell through troubleshooting to the best of my ability. I tried switching to a Cisco X2000 modem/router combo and it did nothing, still totally random latency. Also, when I called AT&T about this, they didn't even know what ping was. They ran an upload/download speed test (which is still mostly consistent regardless of latency) and told me I was basically making the issue up.
I have Wireshark installed but I'm not sure how to effectively search for what might be causing this issue.
Example of experienced latency
Literally 3 minutes later, then it came back 10 minutes after this.
I have Wireshark installed but I'm not sure how to effectively search for what might be causing this issue.