I warped hideously until I switched from cable to DSL (I haven't warped once since I switched a month back), but that has to do with my local providers and neighbourhood issues.
Do this: Do a Traceroute to *any* external IP address.
Identify the first IP address on your service provider's network.
Ping that address (e.g. 50 times). Do you see that some pings are high? Take that evidence to your ISP. They can't blame anybody else if that is happening.
Ping to the first ISP node should be in the teens.
Mxy taught me much of this (the stuff worth listening too, lol).