It needs a oil change anyway, I'm spending it on a good reason. and the oil pressure sensor was bad, I can move it around (the plug) and it would drop on the gauge in the truck. I replaced it, and done a oil change and I haven't had a problem yet.

 

I put a take out motor into my 98 S-10 SS from an express van (98K on it). When it runs hot running down the road it has about 30PSI. Idling in gear it's about 15PSI. I'm running 10W/30 with Lucas. I'm not happy with it myself, but it has been this way since the install in February. I rebuild pumps all the time (Automatic transmission rebuilder) and that one was removed, disassembled, clearance checked, blocked and reassembled. I do wish I had shimmed or put a heavier spring in the relief valve plunger. I cleaned the valve covers and oil pan out, checking the inside of the motor. Full sized van has different add bolt ons (valve covers, intake and oil pan had to be changed) from the S-10. I ran 5w/30 with Rislone to clean out the block for it's virgin run and changed it @ 1000 miles with 10w/30. I ran that for 2000 more, then tried 10w/30 with the Lucas. The only thing I can think is clearances must be on the large side of spec's inside of the motor. I have put 6,569 miles on it since the install. 20w/50 is my choice in oil for it's next oil change. It is what it is for oil pressure. The motor will live or die, but I'm going to do what I can to improve the oil pressure while it's still running.

 

If you want you can try that Lucas engine treatment. I used it a few days ago in a Chrysler 3.3 v6 that has a really bad tick, and little to no oil pressure, and it has damn near 15 lbs idleing now! (They call for 10) and the tick is almost gone.

 

I had the exact same problem, turns out I need an engine. I would check it with a mechanical gauge and go from there.