The steering is active, so it’s uses input from the speed sensor. If the speedometer fails to work it will stop the power assist steering. You car being an import will likely have a speed converter behind the dash, loose connection here on this circuit will be the cause. You tapping probably remade the connection. Also the speed sensor on the gearbox can pop out the end, be loose, simply slowly down and speeding back up it can kick back to life.
By
Stephen ·
http://cgi.ebay.co.uk/NISSAN-300ZX-TWIN-TURBO-/190541721893?pt=Automobiles_UK&hash=item2c5d2bf125
It seems to have the 300zx.co.uk sticker on the rear window. Thought I'd ask if anyone knows anything about this one as my cousins interested in it.