Before you do all that work, be warned. Low oil pressure can also be due to: Innaccurate sender or gauge (you should always check this with a mechanical gauge first). Loose journal bearings (camshaft, crankshaft, etc) -- the pump cannot keep up.
Jim
My 93 4Runner is coming up on 180K miles. I'll need to replace the Timing
> belt soon, at the same time, I want to replace the oil pump. I've been
> noticing that the oil pressure has been lower than normal. I've read a few
> post on the subject recently.
>
> Thanks in advance,
>
> JW
>
>