Your micra on an 86' C/D plate will be using the points system in the distributor instead of the electronic type used from 89' onwards. First thing you should do is take off the distributor cap, check the contacts inside it and check the rotor arm. Then pull off the rotor arm and check the condition of the points, while you're doing this you may as well clean the contacts with a little bit of fine sand paper, same with the rotor arm and cap.
Then check your sparkplugs and ESPECIALLY YOUR VACCUM LINES!!!!! They all need to be sealed and leak-free or everything will be thrown out of balance, even the timing...
I can tell you for a fact that your idle-up box will not be the problem, you can unplug this box and the car will quite happily run without it as long as you don't have everything turned on.
Check your anti-dieseling selonoid by unplugging it (Those two grey electrical plugs on both sides of the air box, one it for the auto choke, if you have one, and the other for the anti-dieseling valve), If it is working correctly then the engine should NOT RUN at all with it unplugged.
The only other suspect is the fuel filter (little white plastic thing on the passenger side of the bulkhead) they can get blocked over time if they don't get changed when they should.
Other than that just check your fuses (drivers' side footwell next to bonnet release lever) Hope this helps...
