02955 well pump. Exisiting pressure set for 20-50psi. Slow to start pump when pressure drops to 20psi. how to reset to start @ 30psi ? Art

maybe bad sending unit most likely or bad oil pump

Sounds line a problem with the water source. A lot of information is needed to answer your question such as model number etc.

On most vehicles, the pump only runs for 3 seconds with the key switch on and the engine not running. But it should maintain pressure.
So you have a faulty check valve in the pump or a pressure leak somewhere such as the pressure regulator or one of the injectors.

You are actually missing air. Your system is water bound. The temporary fix is turn the pump off, drain the tank and start it back up. There is a air volume regulator there that has probably failed.The water you pump has very little air dissolved in it however when it is in your pressure tank; it adsorbed some air from that eventually depleting the air from your tank.

It sounds like there is a fuel leak. Most possibly internal to the fuel pump module. There is an o-ring above the fuel pump on the module that deteriorates and allows fuel to drain back into the fuel tank. It causes a host of problems including yours. Connect a fuel pressure guage, start the engine and watch the pressure increase to @49psi. Then shut off the engine and check the pressure drop. It should not drop bellow 20psi within 10min, and still have some residule pressure the following morning. If not then the o=ring will require replacing, Sounds like its been going on a while. worth a look!

4.9 litre ?? you having a laugh its a 10ton truck engine not a pick up -global warming machine,remove the pump/sender unit and check the gauze filter also look inside tank for a something floating around ,i think the idles is not a related problem to the vehicle losing power but their is a possibility you could have a problem with the little vac operated thing on the fuel injector line that allows the fuel through only when the engine is running

need to drop oil pan check for sludge clogging oil pump pick up

No it is a fail safe. When your oil pressure drops below (on most cars) 30 psi your computer will shut your fuel pump down until you either let it sit for a while and it resets or until oil pressure builds again. Sorry!

Depending on the range of rise and fall, this is completely normal. Oil thins out as it gets hot so you will notice the pressure drop significantly at hot idle. A typical value would be 20psi, then as the engine revs up, the pump creates more pressure because it can now keep up with and exceed the leak-down or bleed-off from the bearings. The maximum pressure would be limited by the relief valve in the oil pump which could typically be as high as 60psi.

Dan,
If your oil pressure actually dropped below 10 psi at idle, your hydraulic lifters would start to collapse. This would cause them to "tick" or "click" at idle. If you are not getting this clicking, change the sending unit.
Charlie