2002 Hyundai Accent misfires

I was called out by a customer to correct a no-start condition on a 2002 Hyundai Accent with a 1.5 L engine. The first thing I found with a Snap On Solus Pro was a code for the Camshaft Position Sensor. Used a Vantage Pro to verify no signal and replaced it, but found a long list of problems with sensors that changed every time I read, but still no start. I went to the wrecker and grabbed a handful of parts, and found that replacing the coils did the trick. The biggest problem after that was hunting at idle, misfire codes, and a converter that glowed cherry-red. I checked for vacuum leaks, replaced sensors, (I was getting codes for everything), replaced the plugged converter, and still had hunting at idle, misfires, and poor performance (low RPM) at WOT. I tried replacing the plugs, the PCM, and cleaned the injectors, and it ran like a champ…for two days. The customer brought it back with a cherry red converter. I would like to know if anyone has had a similar experience with this car, and what would be a solution?