I have recently been having an odd idle issue on my '95 XJ, 4.0L, 5-spd.

It seems to have started earlier this week when I picked my parents up at the airport and drove about 60 miles back on the interstate. Once I got off and stopped at a light, the engine had a very rough idle (and a flickering oil light, so it was clearly idling very low). After a few seconds of idling like crap, it gradually (but quickly) smoothed out on its own. The next day I drove it about 25 miles on the interstate and noticed the same problem. However, today I drove 30 miles and had no issues whatsoever.

My initial reaction is to think a fuel issue (either filter or pressure regulator...with limited exposure to the problem so far, I am not sure if it is too much or too little). Has anyone had this problem before?

I am also having a problem that my heater runs cold which I think that may just be a bad control valve, but I figure I'll bring it up here in case it might be related.