I had tramlining (bump steer) on my miggy, stearing idler was shot and the bushings in the wishbones (apart from one). had it all replaced and had tracking, alignment and camber etc all re-done and she now drives lovely.
I have also noticed the power strearing problem too when i am on full lock and going v.slow, feels strange like something is trying to catch up

From past experience with other miggys i have had i don't think one of them had no problems on the front end, common course for them i think but good when sorted.
Also, where is this speed sensor (i assume on the pump???) and is it a pig to change