Sounds like moisture trouble with the dist cap or plug wires. If your ECU has not been repaired then get it repaired NOW! High humidity or condensation's will cause the currant to short or take another path of least resistance causing the engine to mis-fire. As the ECU capastators start to fail high humidity can cause them to start to short. I know this first hand. My colt did this for about 3 months before the ECU just gave it up and I had to find another! As a newbie I was going crazy trying to figure it why some days it would run great and other days it wouldn't. However like I said I would always check the dist cap and plug wires are good the my next step would be having the ECU repaired with new caps and have it checked for leakage.
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