Rough Idle?

Just reached 200k, has ran great till now. I've replaced the usual, spark plugs(NGK), distributor cap & rotor(factory), wires(Accel/resistence within range). Had osiloscope hook to it 50k ago, injector pulse with odd, but idled fine. The only other things would be the distributor, injector resistor box, or ecu. I do not believe that they have ever been changed. Figured best to ask around before replacing anything else. Any ideas?

Just reached 200k, has ran great till now. I've replaced the usual, spark plugs(NGK), distributor cap & rotor(factory), wires(Accel/resistence within range). Had osiloscope hook to it 50k ago, injector pulse with odd, but idled fine. The only other things would be the distributor, injector resistor box, or ecu. I do not believe that they have ever been changed. Figured best to ask around before replacing anything else. Any ideas?

just for shits n giggles, you should replace all of the above again. 50k is due anyway. I've bought a couple wire sets from autoblown that were bad out of the box. The ecu and resistor box aren't thing's that need to be changed. If they are bad, they are bad and your car would most likely not run at all. The resistor box is just a encasement for 4 6 ohm resistors...nothing at all to it.

Only dianostic was 50k ago, all new accessories install within last month. As for my concern with ecu & irb, was reading from
injectors during dianostics.

u should also check vac lines and hoses... i had a bad PCV from the breather chamber (caused it to idle rapidly from 1500-2500) thx,Lo

Well, problem is that it idles to low, to the point of "almost" stalling. Checked all vacuum lines, had small leak in dashpot line, but only idles high when removed. So no luck with it being something simple, also PCV good. What next? Doesn't smoke at all, just replaced timing belt and tensioner, and yes timing marks were correct. Checked distributor ignition timing not to long ago, so shouldn't be out. Don't own timing light, will try to borrow one tomorrow, and double check.

Is there nobody else with any ideas? So the ecu / i.r.b. should either work or not work at all, but does the contacts on the distributor not get worn?

Well, only one other thing I could think of to check, and that was the IACV, but no luck there either. Resistance was 11.5, within range, and looks functional. Maybe its just time for a rebuild.