Burning oil, worn rings?

Ok, guys! Need some professional input/opinions. Got a 1997 Ford F150 5.4 Triton V8, somewhere around 150k miles all original. Not my truck. Burns oil like crazy smoking blue smoke out the tail pipe. Just had a tune up (done by someone else) I was told it wasn't smoking like this until it came back from a 6 hour road trip both directions. The oil was almost completely gone, barely registered on dipstick, topped it off and it smoked even more. No visible leaks. Check engine light also occasionally flashes. Also idles very poorly, misfires and wants to stall out. It's throwing the following codes:

P0174
P0136
P1131
P1151
P0302
P0171

Everything seems to me like the piston rings are worn badly, and the 6 hour road trips just finished them off. 02 sensor codes could be caused by oil coating the sensors, misfire from oil in combustion chamber, oil could be clogging the catalytic converter. Just wanted to run it by some seasoned mechanics to see what y'all think. It doesn't overheat either.

Get a compression and a leakdown test done.

Seems like damage may have been as result of low or no oil level inside motor. That is sad if the true… However, with all the codes and smoke. Would think of retiring her and look into investing newer or less problematic other truck… But if the truck means lots to you then prepare to have spend lots of dough to fix her up… Mostly engine rebuild… Unless pcv valve is stuck, check that first.

Damaged rings and valve guides. Probably worn bearings if the oil pressure is also low. There's no simple fix. With all those codes you're looking at a major engine rebuild. That should teach you to do a better pre-buy inspection on a used vehicle and to check your oil more often.

Since both banks are reading lean I'm going to assume that you have a vacuum leak. If you find a vacuum leak and repair it then it might take care of 3 or 4 of those codes. Definitely the lean codes, maybe that P1131 since one of the causes listed that can set that code is a vacuum leak. That leaves you with the misfire and downstream O2 code. The misfire could be caused by many different things, I'd say play swaptronics and switch the plugs and coils around and see if it moves to another cylinder. That downstream O2 I would just try replacing it. They don't cost that much on rockauto.com. As far as burning oil I would be more concerned with the valve stem seals than piston rings.

Why do you say rings?
More likely valve guides.
Get a professional mechanic to check it.

You seem to have arrived at a reasonable diagnosis but why not check that with a compression test as opinions will not alter the facts.

I believe you know what's coming next… Go ahead and pull the motor and swap it out for a long block and stick it back in and go again.
I've seen rings break and what your describing is exactly what happens if they do.

Either get a rebuilt motor, junk the thing, or put Iridium spark plugs in it and check the oil level every time you go to drive it and top the oil level up. Next time change the oil a filter every 3,000 miles so this doesn't happen to your next vehicle.

The first thing i would do is check out what the correct compression ratio is. Then do a compression test… Expect it to be down more than 10% as standard… Run engine .remove oil filler cap .chuffing white smoke .crankcase compression… Worn engine… If not a lot i would be looking at valve stem seals… Have you removed all plugs and checked they are not all fouled up…

I like to check easy things first, in this case the PCV and breather hoses. If either has a lot of oil in it you have identified the problem. Usually the PCV hose is dripping with oil, the result of oil getting into the PCV valve one way or another. If there's oil in the breather hose I would pull off the valve cover on that side and check the drainbacks.

I do not suspect the cylinders at all; the sudden appearance after the tune-up (I'm wondering what constituted the tune-up) is a huge flashing arrow saying "look here." I also agree that the "lean" codes are probably the result of the oil contamination.

EDIT - one more thing… The P0302 leaves open the possibility of a blowout in the head gasket or a crack at cylinder 2. I know it is a Triton and removing plugs is not something done lightly, but seeing if the plug has signs of massive oil on it is something you will need to know, especially if there's oil in both the PCV and breather hoses. Compression testing cylinder 2 will confirm or deny the theory. I think a wet test is immaterial if the plug is oil soaked; the cylinder is already plenty wet.