This question is very interesting since I just had to tow my sons car, just after New Years, back 150 mi from school for exactly the same problem. I did change the oil filter, but did one better. I ran the engine with the filter off and clearly could see that I had oil pressure to the filter, also at no time did the guage show low oil pessure, nor did the low oil light come on. Now does anyone know of a specific problem with an oil channel that goes to the top half of the motor? Does anyone know where that oil channel comes up to the top. Otherwise I was planning on pulling the rocker assyemblies off and checking under them, and maybe running a steel coat hanger down the channels.