We sent a sample of the engine oil to Blackstone Labs for evaluation. We're hoping they can give us a better understanding of the internal condition of the engine to see if there may be deeper issues.
Recently, we changed the transmission fluid and filter, changed the engine oil, and replaced leaking transmission fluid cooler lines. Unfortunately, the only access to the lines is behind the plastic bumper / grill unit which surprisingly is only held on by a handful of small bolts.
After those repairs, we replaced the variable valve timing actuator and solenoid (which required removal / replacement of the belts and water pump).
Next up: the crankshaft sensor.
Removing the transmission oil pan proved challenging. The exhaust pipe runs beneath it, preventing removal of the pan. Frustratingly, you only need a couple of millimeters of extra clearance. So we found a 3' crowbar at Harbor Freight, then pried the exhaust down slightly using the floor jack to hold it. The exhaust went right back into position afterwards -- no harm done.