low oil pressure???

ok so heres the deal i have a 98 chevy s-10, its a v6 4. something cant remember off the top of my head. i was getting low oil pressure like less than 20 and it would go down to nothing. now i got my oil pump changed and the grade thing in the oil pan changed / cleaned. but when i got it back my oil pressure would go to 40 when i crank it up and drive it about 10 min then fall to arround 20 and when i come to a complete stop it will go to about 10.... any sugestions? please help

Sounds to me like it's normal. Your engine is a later version than my 1995 4.3, but here are the specs for my '95....

Oil Pressure (Minimum) at Normal Operating Temperature


42 kPa at 1,000 RPM (6 psig at 1,000RPM)
125 kPa at 2,000 RPM (18 psig at 2,000 RPM)
166 kPa at 4,000 RPM (24 psig at 4,000 RPM)Mine has always acted the way yours does, and it runs great, as long as I can keep oil in the damn thing!

Are you going by dash gauge or a manual test gauge?

i am going by the gage but before the pump was changed it was checked by a manual hand pump....

As Tom posted it may be normal.
But recheck with a manual gauge.
Check at idle and at 1K and 2K and 3K and 4K cold and hot
Post back pressure readings.
What weight oil.
Is oil in good condition or does it have a coolant gas smell to it?
Also if not a AC delco oil filter install a ac delco oil filter and recheck.
Fram and cheap oil filters will sometimes lower oil pressure.

ill get it checked asap... but other wise, when the pump was changed, i used to use 5w30 now im using 10w30 i believe... yeah it is a fram filter ill change that out... there is no smell other than oil...