I have water in my oil. It still runs and drives but it knocks

What's the problem?

Code 1443 or 1445- evap system and po325- knock sensor

I keep getting a check code P1441 It is a slow evap leak. I change gas cap. I put new fuel filter in. Change the air filter. New fuel filer hose in. Brand new o2 senors. New exhaust.
I even use shell v power gas only. New spark plugs. what else could it be?

I'm looking to buy a 2001 Nissan Xterra for my son's first car.

It's a 2.4L 5 Speed Manual, I believe 2WD with 197,000 miles on it. The car appears to have been maintained very well however, I do not have any receipts on the truck.

I do not know much about the Xterra, so I'm hoping for advice as to whether we should make the purchase and/or if there are any parts of this vehicle in particular we should take a look at.

Thank you in advance!

with the a/c off car runs fine all the time

I just bought this vehicle Wednesday from a used dealer. Drove it all the way from the dealer to where I live, different counties. Noticed some smoke but figured from the heat being on, was told that isn't the case. Used a car MD device and the only thing that came up is a code for a replacing the part that stalls the knocking for a engine, nothing major. Please help!

Makes a strange whirring noise now. Just before it died the wipers started going really slow. Headlights work, battery terminals are cleaned and it's a new battery

What causes my X-terra to struggle moving forward after I put it in drive but after a few minutes warming up it will move but struggles for the next few miles. Will this be a costly repair?