It may be typical these days but it's not normal. One of the things that impressed me about the car when I bought it was how smoothly it idled. You could've stood a coin on edge. The last car I worked on, one saved from the junkyard with a JDM engine later installed, idles nearly as well because I went completely through it after replacing the HG.
While there are many causes behind misfire the trick is first finding out which cylinder(s) are involved. An ignition scope will quickly pinpoint that or rule out the ignition system altogether. Scoping the O2 sensor while triggering off IGt is another way to see who's at fault. So is measuring exhaust pulsations. Larger misfires can be found by using an IR thermometer on the exhaust manifold. Using smoke on the engine is also very helpful. Once the cylinder is identified it's a lot easier to track the problem down. Often the cause is mechanical ie; pirate air, valve clearance, poor valve sealing, deposits, ect. That was the case in the few times I've come across it. The EFI system is rarely the culprit behind any problem on these cars as long as it's been maintained and not been screwed with by those who don't understand how it works.
Since by law OBD-II is so much better at ferreting out misfire it's a pity we don't have it. That said the ecu in the 7M can do it, it just needs to happen under certain conditions and even then it's not very accurate. The code involved is 25. OBD-II looks at the speed of the NE signal just after ignition. It's a much more sensitive method of detecting misfire. That said the causes behind it are the same in any engine.
