I have a 1985 nissan sentra and my car has been stalling on me alot. Whenever I come to a stop or when I put it in neutral it'll drop down to like 100-200 rpm then 10 secs later it'll just die on me.I have went to the junk and replaced my ISC but it still does the same thing.I have replaced my distributor and rotor, spark plugs, fuel filter, and pcv vavle. Also how do I check my ECU for any faulty problems.
If you have a normal distributor, try advancing your timing a little bit. My truck was having the same problem and adjusting the idle screw would only work for a bit. Advancing the timing has worked for me. You might even notice a little bit of a power increase because your timing belt/chain may have stretched a little over time causing the timing to be retarded.