http://store.driftmotion.com/static/...dedoilpump.php
The 7m is known for low oil pressure, hence this upgraded pump on driftmotion. And if you have 190k on the pump then it probably has its share of wear on it. It is also a good idea to measure the pressure with an accurate guage and not the oem dash gauge.
http://www.cygnusx1.net/Supra/Librar...Section=LU&P=4
But if you do need to replace the pump, it won't be fun. In order to drop the oil pan you will either need to pull the motor or drop the subframe.