What would cause my truck not to have any oil pressure

you need to first check your oil sending unit,,,then if ok the gauge/light.....is it running ? give us more info !!!! please ....how long has it been since you changed the oil/filter........??? does it have oil???in other words, why go on here with reasons why??? when did this START? tell us everything you can- ok and we can figure it out>>>>

Husband started the truck for the first tone today. There was no oil pressure. Had pressure yesterday when we parked the truck. Changed filter and oil 5 weeks ago. Yes it has oil in it. I came on here to ask because I have check everything I know to check and can't figure it out. Short of spending a lot of money taking it to the shop.

Does the engine make any clattering sounds when starting it? If not it likely has oil pressure and the oil pressure sender or the gauge has a problem. What needs to be done is the pressure needs to be measured at the oil sender with a mechanical gauge. If there is indeed no or low oil pressure the cause needs to be diagnosed and repaired ASAP or severe engine damage can occur. Possible causes of the problem are...defective oil pressure sender, oil sender wiring unhooked or broken, problem with pressure gauge at the dash, plugged oil pump screen, defective oil pump or other engine issue. How many miles on this vehicle?

There is a screen basket under the oil pressure sending unit that collects debris and gets clogged up preventing the sending unit to read right. Take out oil pressure sending unit and fish out that screen and clean it. May want to put a new sensor since you are there.

Rowefast, good answer. I forgot about the screen.

Thank you...