Dylan Paetsch

Hey, so ive seen this posted a few times now and im aware its a common issue but i thought i wouidl dig it u again since i dont see anything recent on it or specific to my issue... Here goes... (excuse my grammar/spelling errors) I have a 2011 Silverado 5.3l Crew Cab with... (drum roll) an oil pressure issue! What a suprise. Code p0521 "oil pressure performace". It initially happened about 5 months ago in the summer and the pressure zero'd out after driving a short distance. I took it in, oil pressure was fine but instead of doing the inevitable of changing the sending unit and screen we decided we would try replacing the oil (it was overdue and pretty dirty) and also do an engine flush to try and get rid of the crud. This actually worked! Oil pressure hovered around normal (275kPa/40psi) when in idle, after running for a bit. No CEL. I drove it for a 4 or 5 months (im still about 2k away from my recomended oil change) and then we had an EXTREME cold snap where i live. Upwards of -40C with the windchill for an extended period of time (it was hell). Hopped in it one day to go for a rip an noticed the pressure drop... and drop.... and drop.... annnnd CEL..... and 0 oil pressure.... alarm. it would do this everytime i drove it, even just heading up to the store quick, it wouldnt take long until it eventually would just hover around that 1/4 mark (137kPa/20psi). I decided to have the sending unit and screen replaced. Got a call back, they put an actual reading on the pressure... good, changed the sending unit AND screen... good, cleared the CEL... good. Started it up to take it home, pressure read higher than it did, but it had been sitting outside, cold. Parked it, woke up the next morning to take it on the highway, didnt even get out of town.... CEL. Warm oil pressure while idling roughly 137kPa/20psi.... increases a bit at higher RPM and highway speeds, but not much. Ive been driving it about 4 or 5 days now, no change. It doesnt go into alarm, at least witht he distances ive taken it but the pressure remains low and CEL SO... the infamous P0521 error = replace oil pressure sending unit seeand screen ms to be incorrect in this case. Ill state some obvious facts before asking wtf is wrong with this thing to weed some things out.... 1... yes, ive checked the oil, its fine. Perfect level and doesnt appear dirty. 2. Engine temp has always been normal runs at about 100C/210F once warmed up and idling/driving. Never has it increased.... What im getting at here is that im fairly certain (i think?) that the engine is not starved of oil, the levels are fine and the engine isnt overheating. It seems to still be an issue with the sensor sending false information to the engine. But why? Ive heard to check the Ohms on the harness to the sending unit? But i cant seem to get much information on that. Is there anything else it could be? Im leaning possibly towards the fact aswell that i may have waited to long between oil changes and i have alot of buildup in there from doing so. Are oil changes and engine flushes going be something i will have to do more regularly now as a result? I guess that wouldnt be the end of the world... Anyway, any feedback would be awesome, Thanks in advance. (the pics posted here are of the code (duhh) and the other is of my dash idling after driving for a bit/warmed up)