Sorry, for the attention-grabbing headline (hopefully), but really trying to get my wife (and kiddos) back on the road ASAP.
We have a 2006 LR3 HSE and it's been great. We've had it for 5 or 5 years; since 90k. It now has 170k! No major repairs....so far.

There's Jag V8 valve-tapping sound, but nothing to note. It's always been like that. I replaced the thermostat (PITA) a few years ago and the battery a year later, but other than that. It's been phenomenal. My wife really likes the way it drives and the safety aspects, so we'd really like to keep it mobile as long as possible.

Anyways, my wife messages me today that 'the car is smoking like crazy! And I can't move when I give it gas". . a few minutes later, another text, "It's not smoking anymore and seems to be fine on the highway." I asked her if the temp gauge moved, nothing there. I get home about an hour later and the car is sitting there. I check the dip stick and oil BARELY registers on the bottom of the dip stick. I fire it up and sure enough, it's smoking bad...like really bad. I run around the back and check out the clouds, pretty blue and pretty gassy smelling. I shut the car off. . do some Google searches, but ultimately wind up here.

PCV issues, piston rings and burnt/stuck valve are all potential culprits, right? Anything major and/or consistent you've seen with these symptoms? To me, it seems to be consuming oil rapidly (just had it changed 900 miles ago). I would think it would have something major for it to smoke that much and consume that much oil.

Oh, she was also getting that 'REDUCED PERFORMANCE' message on the dash or whatever it says. . I'm nervous this will require MAJOR repair.
I know I might be jumping the gun, but IF that's the case, do ppl have a preferred engine swap they do? (i.e. LS1, BMW V8s, etc? - any known 'direct' drop in setups? Again, my wife really likes the look and feel of the car).

Thanks in advance!!

Waiting on your input for next steps.

 

PCV is the common culprit.

There is no common or drop in swaps I'm aware of aside from a good 4.4 jag v8

 

I second a PCV