Sonata NF (2006-10) :: Slight Noise At Start Up - No Codes

My sister has a 2006 sonata V6 3.3, she got in 2007 with I think 20,000 miles on it, it has 180k. now. For the first few years she took it to the dealer for all the maintenance and oil changes. She has kept up with the oil changes and I think all the recalls were done.

There has been so slight noise at start up, but nothing I thought was too unusual for these kind of motors.

Yesterday she had an emergency with one of the kids, her faithful sonata fires up with an incredible amount of upper end noise, and it looked like it was burning oil. The engine was turned off immediately.

Her husband tried to start the car about a half hour later, he said it was hard to start, ran rough for moment, he revved it for a bit and it smoothed out running normally. No codes and no CEL. Oil level was good. Oil filter is a fram I think.

I started it a few hours later there was some lifter noise that quickly went away after a rev. Other than that it sounded normal and drove normally, normal exhaust from what we can tell.

There were no codes. and so far it has not done it again. But she is worried the engine is about to fail and she can't trust it with transporting her kids.

Was a timing issue? stuck valves? oil pressure? Oil Pressure to the cvvt (OCT?) maybe? They can't afford a new car right now, is this something easy to fix or is it a warning the motor is about done?