What type of oil pressures do you guys see, i've noticed when warmed up at idle the pressure drops to around 22-25 PSI and its slightly concerning.I know that the FSM States that it will do single digits at 1200 RPM but it still seems on the low side for 140k on the motor.

 

Oil pressure varies alot with temp; in the photo the coolant temp is low as in engine not at operating temp yet...so I would think the oil pressure would be higher. On my Blazer with new oil and a cold start, mine shows 60, gradually drops to around 40 when driving and then a bit lower at idle.
The oil pressure sender used is not the most reliable one....and I would suggest changing it or best would be to temporarily connect an actual pressure gauge...however getting to the sender is a ROYAL PITA!

 

Just today, at about lunchtime, i changed my oil with 5W-30 High Mileage. Regular conventional oil from Walmart. Made by same people that make name brands. Thirteen bucks.

My previous full I had a quart of MMO (Marvel Mystery Oil) in there. For cleaning.. in the case it needed it. If not? Harmless. That all came out at my oil change. Warmed engine.. some feel this matters, and indeed, it may .

My old oil pressures were about 10 at idle, and halfway up the gauge when driving, 75MPH on highway etc.. maybe a tick above but not much.

It now seems to idle more at like 20psi and be more like 50 driving down the road maybe almost 60 cold.

I will have to see if it stays like this long trips full hot etc but.. maybe that old oil really does lose its effectiveness.

BT, DT. On my first gen before we condemned the engine to being replaced..

Get ladder, lay across engine, specialized tool, 15mm I think. Comes right out just requires contortion and a ladder (that's how I did it. Laying across engine.)

It is by the Distributor.