Not sure if this will apply to your case just thowing it out there. i had a similar problem with my car, at the top end of the track it would stop pulling and sometimes regain just before the end but not always..after checking everything I could think of..turns out it was my fuel delivery system, mainly the filter I had between the tank and pump...last week at the track it did it and this time I looked down at my fuel pressure gauge...it was zero.....checked the plugs in the pit, very lean, I was running out of fuel when I needed it most, not because of the pump but the filter had debri in it....just a thought.