03 LB7 Injector change

I am new to this page and fairly new to the diesel world. I have a 2003 LB7with roughly 180,000 miles that I have been told needs new injectors. It still has plenty of power but gets a knocking sound that gets louder the longer I drive the truck. I've had several different people look at it and without tearing into the engine everyone has been stumped. Some seem to think it might be an injector issue. The only thing I've noticed that's different besides the knock is my oil pressure stats real low now. The pressure is good when I first crank the truck but after it warms up and I come to a stop it drops back down to right above red, when I take off again it picks back up. Any help or advice would be much appreciated, thanks.

It's hard to gauge the severity of a "knock" though the internet, but what I can tell you is if it is a fuel related knock (especially if accompanied by black smoke) then I would discontinue driving it before you break a piston.

Injector balance rates are a very basic starting point. They may not pinpoint the issue, but they could put you on a path to the solution.

I should note that I am often dismissive of balance rates when a guy has symptoms like fuel in oil or heavy white smoke. In cases like these, the injectors can function relatively normal yet cause the symptoms and the balance rates will look just fine.

Welcome to the board!

Low engine oil pressure could be due to fuel dilution, because of bad injector fuel return line(s) seals or a cracked injector body.

Put a drop of oil off the dipstick on a clean white paper towel. If you are able to clearly see two concentric rings form, there could be fuel in the oil.

Kennedy, no black or white smoke. Took it to a friend of a friend at the chevy dealership, he hooked up to it at idle and going down the highway and he told me the balance rates were fine but that if it could still be a cracked body. I also took the truck to a local repair shop and told them what was going on left it over night and they tried to tell me the next day that I was going to need a to completely rebuild the engine for $10K. I can't remember exactly what he told me but something to do with a pin out of wack. I really think they had no idea what it was and knew I didn't know what it was so they were going to try and get over on me. That was towards the end of last year, since then I only drove the truck around town and never saw anything really get worse except for the fact that the longer I drove (couple hrs or more) the knock would get louder but after it would cool down it would go back to barely noticeable. Several people said they couldn't even hear it but I drive it on a daily basis and it's definitely not a normal diesel noise.

More Power, thanks for the paper towel trick. The problem is I'm in the military and in the desert right now but will be coming back home soon. I will have some time off before I have to go back to work and want to fix the issue while I'm off.
I had pretty much already decided that I was going to change the injectors when I got back but decided to ask y'alls advice first.