2004 Honda Accord sedan, 4 cylinder, appprox, 95,000 miles, uses oil rapidly at highway speeds (one quart in 90 minutes), in town driving will not use any oil over 3 to 4 months of monitoring.
Any ideas what the problem is and how to fix it?
The crankcase vents are likely plugged.
+1
The first thing to check is the PCV valve and the line leading to it.
More than likely, you will find both clogged with gunk.
+2
A compression test would be a good idea too. Worn cylinders and/or tired rings allow greater pressure to build up in the crankcase via more blowby.
The older Honda 4 cylinders, 96-98 had an issue with the oil seals. While the problem was solved for the later years, it is possible that it could be a random event with the oil seals. Normally Honda’s at this age and miles do not loose any oil at all.
If the PCV valve is gunked up, then I would have the valve cover pulled and check the oil drain back holes. I would suspect that if this engine is gunked up (sludge build up), then it have very poor maintenance.