I would just put in 20W50.
Your miles are not that high at all.
'between 6 and 60 psi' is very normal for that engine ..
that's 60 cold 2K rpm,
6 psi hot idle rpm.
Totally normal.

I don't use STP anymore. I might use Lucas Oil Stabilzer .
I have a few engines just like this ..1.9 wbxr with fresh heads, some
miles on the bottom end.
put in a quality 20W50 ...
expect 60 hi, 6 psi low. You'll be fine.

it would be silly to own an otherwise very useful vehicle, butdare only
drive it in easy conditions. Like what's the point ?
"I love my vehicle..
but I never take it on any real hills in the summer."   No pass. lol !

On 7/15/2013 11:43 AM, Stuart MacMillan wrote:
> Ignorance is bliss, at least for a while.  My worn 1.9 with 140k miles runs
> 5-8 psi idle after a run on the freeway, and 22-26 psi at 3000 rpm when hot
> with Mobil 1 15w-40.  Pressure is 60 psi at cold start up. This is in nice
> temps, about 70 degrees, and mostly flat terrain.  I knew it was bad, but I
> just want to get another 2000 miles out of this engine, and I'm staying on
> the NW coast this summer to avoid long climbs and hot weather.  I wonder if
> 20w-50 would boost it a little.  STP?  Or just forget about it?
>
>
>
> What do you think?
>
>
>
> Stuart
>