Bad oil pump or faulty gauge

Please help, I want to make sure I'm not damaging my engine. My idiot light goes on and it says I have 0 oil pressure, but only does it on acceleration and occasionally at idle. At longest it stays at 0 2 or 3 seconds then jumps to 40. The rest of the time it stays around 40. No unusual noises such as knocks or shudders happen while it's at 0 either. It doesn't drop everytime either which makes me doubt a mechanical failure since it's not consistent at all. My gauges always fluctuate, but the oil has never gone that low. Would it be wrong to assume a bad gauge cluster or should I worry about the pump? All my gauges except the speedometer jump around from time to time.

What year? What engine? Some models had issues the oil pickup.

Sorry I'm so frustrated I forgot important details. 96 k2500 with the 5.7 and 5 speed manual. It's also worth noting it's at 225k miles and I'm overdue for an oil change, been about 8k miles since the last one. That'll be done this week

Got it figured out. Just for informational purposes I'll explain. Folks, your dipstick may not be as reliable as you'd think. I was in the process of changing my oil pressure switch and noticed a lot of oil build up ice never seen before. Turns out, even though my dipstick reads full, there was hardly anything in there. I drained the oil and there was maybe 2 quarts that came out. Checked the oil and it showed at the bottom of the dipstick still. I ran 5 quarts through and immediately drained to make sure there wasn't a lot of build up or anything. Oil came out mostly clean. I put in a hair over 5 quarts, 6 quart pan, and then re checked the dipstick and it showed way over full but the pickup ran great, no pressure problems, I drove it to cheyenne and back, roughly 115 miles, and no issues, obviously not over full. And the dipstick showed waaaay too full. Must not be the right dipstick. Just shows that the absolutes in the automotive world may not be that absolute. Makes me wonder how low I've been running the engine and for how long.

I suggest you get a tape measure and measure the length of your dip stick. Go to a junk yard and measure one from a same size engine.
Obviously you
need a proper length dip stick.
Unless you purchased the truck new I think the previous owner purchased a wrong size used dipstick.

use tape measure go to scrap yard see if the stick is correct... if so the oil pan full of goop.

The oil pan sounded very hollow when I knocked on it, trying to see if it was actually empty. No signs of being overfull either. I feel like if it was full of goop it would sound solid, or at least like it is absorbing noise like a wall with insulation vs. A wall with none.