[BC] Intermittent Ping Spikes

I've been with Shaw for 6 months now and been very happy but lately I get horrible ping spikes... If I run a continuous ping to google.ca for example, all ping are 20ms but every 20th or so ping will be 400+ and up to 1800, sometimes even timing out. This happens from my PCs inside the network as well as from the modem itself. I've rebooted it and waited 2 weeks, still an issue. Makes playing a fast paced online game like Battlefield completely unplayable. I had this issue with Shaw before at a place I lived and ended up switching to Telus because Shaw's techs could never do anything about it even with repeated tech visits. Hence I'm posting here before calling them. It's hard to get them to look into this type of issue when speed and connection tests all pass fine. Any suggestions?