Hi everyone. I've been having alot of issues over the past 2 days of my truck losing oil pressure under load. I was 600 miles over my oil change so I decided to change it to see if that would help but it didn't make any difference. The gauge will read normal and you can baby the truck through town to keep it in the normal range but as soon as you give it a load (around half or 3/4 throttle) it will begin to drop and if you hold that throttle up to around 3k rpm it will eventually read that there is no oil pressure at all. I have a lifter tick that I've tried fixing on many occasions but haven't been able to and I've been running it for around 10000 miles plus however long the previous owner did. I have done looking and I see that oil pressure gauges are common to go out in these engines but would it act like this? I am also seeing that the pickup tube could be clogged, it could have bad bearings, or the oil pump itself could be going out. Any help is appreciated. Thank you