The dash digital oil pressure display stays at zero when the engine is running, all RPM's. Verified that engine oil pressure is about 45 to 50 lbs at idle and that the oil pressure sender on engine is working (replaced). Removed electrical plug from top of oil pressure sender and oil pressure display goes to 100%. All other dash digital displays, speed, engine temp, tach are working OK.

Hi assuming the oil filter has not become blocked, it sounds like the oil pump is not working properly. Of course it could be something more simple like a faulty gauge, sender or bad connection. But assuming again that the engine is suffering from oil starvation, I would get it checked quickly before you seize the engine completely. Good luck!

The oil pressure should be verified by removing the oil pressure sending unit and installing a gauge to take a direct reading. If the oil pressure is ok, the problem is most likely a bad pressure sensor (although it could also be a bad gauge or circuits).

If the gauge verifies that the oil pressure is indeed low, then the oil pan needs to come of for an inspection of the oil pick-up tube and the engine bearings.

It sounds like the oil pressure switch has failed. It is only an on/off switch that trips at about 15 - 17 PSI, the reading displayed on the dash is created by the computer based on the pressure switch being closed and the engine RPM.

Possible that the OIL filter is clogged and is reducing the pressure due to this when the engine is idling or in low RPM. So before you run the engine further and make it more damaging , it is worth to have the engine oil / oil filter changed. If there is still no result, check the oil pressure switch. If not the oil pump can be faulty. This needs a technical help and should be consulted.

Measure your oil at normal operating temp, without the engine running of course. This will give you a more accurate reading once the oil has circulated in the system.

The system works like this:

• With the ignition on, the oil pressure indicator light on the dash should come on and flash. Once the engine is started, the light should go out and stay out as long as the engine is running.
• If the oil pressure drops below approximately 0.3 bar or 5 psi when the engine is running below 2000 rpm, the light will flash.
• If the oil pressure drops below approximately 1.8 bar or 27 psi when the engine is running above 2000 rpm for more than 3 seconds, the indicator light will flash and the buzzer will sound.

If either this two warnings occur:

• The engine should be switched off immediately and the oil level should be checked.
  

you must obtain an oil pressure gage you can use a inexpensive type like you would hang under your dash. remove the oil pressure sending unit from the engine, a little oil will leak out when you remove it, no big deal. install the add on gauge and see if the pressure at idle with the engine warmed up is over 20 lbs. if not you probably have bad crankshaft bearing but you would want to see what htings look like inside the oil pan.if the pressure goes up to about 60lbs when running fast. and is very low at idle the engine is probably worn out. if the oil pressure drops when it is running fast you may have a plugged oil screen.i have found paper towels and rags inside of engines.

check the oil descending unit or ur oil pump might b clogged up with soot, just some advice hope it works

I have a 99 blazer and ever since I have owned it, it reads lower in pressure when idling, but will go up too 40 while driving. This is normal for the vehicle. If the pressure gets real low, and stays low, it means its time for an oil change.

As long as the pressure goes up when you give it gas, it is fine.

Check the oil pressure with a test guage, if the finding are the same, the look at your oil filter, pump, pickup, or pressure relief valve.....

This is a normal occurrence. The oil pressure is directly correlated to engine RPM. your check engine light is related to something else.