Toyota Repair: engine knocking, drive belt tensioner, power steering pump

Question
Have contacted you before. Good info.  My 2000 Toyota Corolla automatic has 130,000 miles.  For the last couple months there has been a knocking sound around the  lower  engine passenger side. Especially in cold weather. When it warms up it seems to go away.  In the area of possibly(?) the power steering pump maybe. ( could a bearing be going bad?) The PS pulley while stable has  a slight wobble. In the spring and Fall I spray WD40 on the pulleys to clean and lube. Seems to help the problem temporarily. Or could I be offbase.
Thanks again Ted.

Answer
This noise is common on the Corollas, it's the drive belt tensioner, it becomes weaker over time and starts to vibrate, this causes the noise, Toyota had even issued a service bulletin for this, the remedy is to replace the belt and the tensioner, aftermarket parts may be used, try to stay as close to OEM as possible, they are a little bit more expensive from the dealer.