Bought the car with high mileage 140k expecting to have some issues...but!

So far I've replaced the Opti, water pump, plug wires, both converters and both 02 sensors, the EGR valve, did a fuel pressure test and injector leak down test, and tested the resistance hot and cold on all injectors. Fuel pressure and leakdown test were negative for problems, and cold all of the injectors were between 12.3 and 12.5 ohms, and hot they were all between 12.7 and 13.0 ohms, so I am assuming that they are not the cause of my problem. Also checked was the fuel regulator which appears to be working normally. I bought a vacuum gauge and at idle I show 18inches of vacuum and it appears steady, fluctuates between 17.5 and 18 inches. I've identified and replaced a couple of spongy vacuum hoses as well.

Although I instructed the dealer to replace the opti harness while he had the opti off he neglected to do so and stated that it never goes bad. Everything that I've replaced so far has made the car run somewhat better and from the point of view that I am going to keep the car for a long time and the mileage it is money well spent, all of this is bolt on so even if I replaced the heads and block I can still reuse these new parts.

Now I am at the point where I can start wasting money on parts and am looking for some help as the dealer was convinced that my problem is with the Opti. I am going to go ahead and replace the Opti harness because it's cheap and according to these forums may indeed be a problem. The car has since thrown a 13, 16 and 32 code since being returned from the dealer about 6 weeks and 200 miles ago.

The car runs like a raped ape other that this random miss/stall. Also, it starts and restarts easily, even after it stalls. 2 turns and it's running. Any ideas?

Thanks
Terry