Personally, I think that if the cylinder scoring hasn't shown up after 165k miles, it probably won't. Beyond listening, you can have the cylinders boroscoped via a pre-purchase inspection. It's a simple process - just remove the spark plug and stick a camera down there to check if there's any scoring on the cylinder walls.

That being said, aside from the cylinder scoring issue, there are other things to consider when compared to your gen 1 truck. They're largely the same, so some things to look out for:

1.) The engine is now direct injected. In your current truck, it's port injected, so the fuel is applied behind the cylinder valves, effectively washing them off with the detergents in the fuel. The direct injected engines have the fuel applied directly inside the cylinder, so the valves are no longer cleaned off. There are ways to clean off the valves, and I'd imagine a 165k mile engine has some pretty good carbon build up that would benefit from it. In addition, there's a high pressure fuel pump that, in general terms and related to all DI engines - not just the Titan, seems to be more prone to failure. The high pressure fuel pump is also pretty pricey. So it's an additional concern at high mileage over what your old truck has.
2.) Different transmission, but about the same reliability-wise. I would check the service history to see when/how often the fluid was changed.
3.) The rear diff doesn't have the same issue as the gen 1 trucks since it has a proper vent, so that's a positive.
4.) The rotors are the same as the gen 1 and prone to warping, so check that out.
5.) The design of the exhaust manifolds is similar to gen 1, so again....at 165k a cracked exhaust manifold wouldn't be out of the question.

These trucks are pretty dang solid, all things considered. For $15,900, hopefully you have some room for miscellaneous things going wrong over the years. I've had to have the clutch fan, evap charcoal canister, passenger exhaust manifold replaced so far at 75k miles but otherwise I just keep her maintained. The exhaust manifold actually cracked near the outlet flange and could have been easily welded at an exhaust shop for about $50, but since it was under warranty I opted to have Nissan replace it free of charge.

 

and another odd thing is the engine being changed won't show up on carfax. only the dealer might be able to tell you that and i think only if they did the swap. they are kind of weird on their records so sometimes other dealers can't see stuff.

i feel the same as above, if its not knocking by now, it probably won't since most do it in the first 30k to 50k

 

I can't thank you guys enough for taking your time reply and give me solid advice. Your reply's will help me greatly on the direction I go. For the record my 11' SV has 235k on it and it still runs great. That's why I'm exploring a Titan again. I would keep her (and maybe I should) but I would like to get a crew cab truck.

 

understandable. my wife picked our crew cab 2017 titan. i don't know why she wanted a crew cab because 99.5% of the time, its just us but i understand needing one if you have kids. they are great for kids because the back seat is huge

 

You have the knock of death on your '17?

 

You could have the seller send you audio/video in the drivers side front wheel well when the truck is warmed up. Should be able to hear the knock if there is one. If so, it would save you a trip.

 

Great Idea