I have a 1991 Dodge spirit. The car will start and I have noticed that the oil pressure gage is low. When I stop at a light the pressure goes lower.And I also noticed today after driving 300km the engine was still quite cool.I am not a handy person on cars so any input on what you may think the problem is. Is greatly helpful. Thank you

Well the check gauge light is telling you to check your gauges, because of the low oil pressure. It could be a sending unit problem, or the oil pressure really could be dangerously low. Should be at least 25psi at idle.

If I undersatng your question, the oil is picked up by the oil pick up under the oil pump inside the oil pan, then t goes inside the engine block casting, that has several lubrication galleries running paralell to the crankshaft and the camshaft. the head has some oil passages to let the oil drain to the pan, and tha completes the flow.

Okay What it means is that the oil in your car is either low in level or the oil pressure at low revolutions is low. I highly recommend you to stop driving the car when this happen because you can internally damage the engine with a low oil or a low pressure of oil. Check the oil level first..make sure level is fine and oil looks good. Black and burned oil will give you a low oil pressure as well. If it happen that your car need a oil change. Make sure you get it done and see if the problem goes away. Very rarely oils pressure sensor goes bad but if oil is new and level is fine you can take the oil pressure sensor and connect a tester for a oil pressure. If this is not under the manufacturer specifications.. oil pump is worn out and you have to replace it for a new one.
Good luck and don't forget to rte me. Thanks

If this is a loud knock from lower part of the engine then its the crank bearings, I personally think that the engine is done.

Might be a bad Oil pressure sensor or a weak oil pump and when the car idles the pump even if it spins but the power is low but after you push the Gas then the RPMS goes up and the pump spins fast the pressure gets higher. Good luck

The "check gage" when ever the engine coolant is high or the engine oil pressure is low. First step of diagnosis, check the coolant level and your oil level immediately and then go from there. Hopefully, this will help you to FixYa problem!

the cluster module may be at fault-disconnec batt for a minute 1st--make sure u grounded the new unit

CHECK GAGES light (1) indicates a potential engine failure(low oil pressure, low coolant, coolant overheating) has occurred.
· Check gages and shut down engine. Gages should read as follows: Oil pressure 5 to 10 psi (34 to 69 kPa) at idle; Water Temp gage below 230 degrees (110 C).
· Check engine oil level (Para 2-11) if OIL PRESS gage indicates low reading. Check coolant level (Para 2-11) if Water Temp gage indicates high reading. Notify Unit Maintenance if levels are low.

If CHECK ENGINE light (2) is on, check engine oil pressure gage (3) and water temperature gage (4). If both indicate normal, proceed with mission and then notify Unit Maintenance. If either one does not indicate normal, stop engine immediately and notify Unit Maintenance

Yoyu dont mention the mileage on your Yukon but low oil pressure will indeed light the CES light when it reachs o psi. Have you checked your oil? Have you changed your oil and filter. High mileage and poorly maintained motors will eventually wear out and develope low oil pressure. A tempary cure would be to use a higher weight oil 20w50 will get a few more miles out of the old gal if indeed the cam, main or rod bearings have reached their service limit.. Good luck

change oil filter use a k&n or mobile one,seen same problem on caravans some oil filters cannot take the pressure and break up inside causeing no flow of oil period.could happen at any time with cheap oil filters,chryslers have high volume oil pumps and require a better flowing filter.
as for your engine not starting you may have severe bearing wear,from low oil pressure.