Please Help, Error code P0011 and P0021

[Allseasonslogcorp]

Please help.
I have a Nissan Quest 2009.
I'm getting error code p0011 and P0021, I already tried changing one of the solnoids in the front and also changed both Camshaft position sensors. I also changed the oil and the filter on the car, after that removed the code and still it reappears . I don't know what to do anymore . I'm going to change the oil pressure sensor next and also the solnoid in the back of the engine.
The van has no power lost, run goods , changes good, only other thing I remember was putting an additive (STV high mileage oil treatment). I don't know what else to do? If anyone can help that would be awesome, thanks.

[far raf]

1) never ever put any additives in fuel, oil or transmission fluid. all additives are snake oils peddled by unscrupulous crooks. if you want high mileage oil, go with that by a reputable company, such as Castrol or Valvoline.
2) your intake timing valves are failing to deliver pressure to the variable intake system. Do an oil change for what I mentioned above, give it a 100 miles and read codes again.

[Allseasonslogcorp]

Thanks I'm gonna try that and let you know, how it goes.

1) never ever put any additives in fuel, oil or transmission fluid. all additives are snake oils peddled by unscrupulous crooks. if you want high mileage oil, go with that by a reputable company, such as Castrol or Valvoline.
2) your intake timing valves are failing to deliver pressure to the variable intake system. Do an oil change for what I mentioned above, give it a 100 miles and read codes again.

[YELLOW S13]

I just dealt with this replaced alot due to p0011 code took upper intake manifold off figured while im there replace coil packs spark plugs etc. Changed the intake valve solenoid put it all back together and had p0021. Cleaned it replaced it with anew oem as well that code never went away. Turned out it was the timing chain skipped a tooth. Guides were done as usual. We initially though it was the oil galley gasket not getting oil pressure where needed. Just fyi this could be costly unfortunately was the case with mine

[Infinibat]

I am getting the P0011 and P0021 error codes, changed the oil and filter,removed the solenoids and they seem to check out fine, put 12 volts across the coils and they function correctly. I put the solenoids back in. I then looked at the WIX oil filter I just replaced. I now see that the rubber anti drain-back valve is damaged, some of it might be missing. I am thinking that the rubber is now somewhere inside the engine in an oil passageway, blocking the oil from getting to the solenoids. Will i need to have the engine torn down? I don't know. I have not taken it to the dealer yet, but that will happen soon, I suppose. This could get expensive

[far raf]

What year? Considering the age, it may be not worth touching until wheels fall of.