A time warp was a kind of time loop. It could be caused by gravitic warping of normal time-progression, resulting in lateral stasis. The Flying Dutchman II had been trapped in one for 628 years. Kroton the Cyberman helped to break it. However, this resulted in the passengers rapidly ageing to death. (COMIC: Ship of Fools)
Time warps, which felt like being "tumble-dried," left a temporal residue that could be detected. (AUDIO: We Are The Daleks)