1988 Mazda 323, power surge at end-stops of steering

[MidAtlantian]

1988 Mazda 323 with power surge at end-stops of power steering.

Hi, i know that there is a vacuum activated when the steering comes to the left or right ends, and that gives more power to overcome the power the power steering pump takes, but my hatchback's over-power seems to have got a lot stronger. When I steer hard for parking, the engine really surges ahead. It is a bit dangerous! - I never remember this as a problem. Any ideas on the this?
Thanks,
Midatlantian