do some graphing, click 'view points' and zoom in on that area. you'll see there's actually a data dropout at that point.

general wiring fault, a loose ground maybe? that'd be my first guess.

edit: i notice a lot of WOT events have this happen. this really points to loose wiring. when an engine flexes the engine mounts to their max, maybe it's yanking on a wire. this is common for swaps when not enough slack is allowed.