1990 300zx caught on fire... ecu?

[DenCoZ]

I have 1990 300zx n/a. It has had a motor swap to another n/a motor. I have been driving the car for a year and a half since the swap. I have been trying to Chase down a mi fire issue. J have swapped the coil packs, the ptu, I have the correct ngk plugs in it. I was beginning to think the misfire was a bad injector and have been saving up to change them all to the series 2 intectors until...

The car was running like normal(with misfire). When I pulled into my driveway I heard a pop and smelt something, smoke began coming out from under the hood. I popped the hood and my 1 cylanders coil pack was on fire. I put it out. It looks like the fire started when the pack plugs in. I rewired a new connector. In testing I noticed that the center plug is reading ground. So there are two grounds in the harness. None of the other book pack plugs have this. I plugged in a new coil pack just to test. I had the key in the on possition car not running and the pack popped and almost caught of fire again. I chased the wiring harness and looked for damage. There is nothing all the way to the firewall. Leaving the 1 cylander unplugged the car runs like it always has and must be where my misfire was. Since I have already replaced all the components in the system other than the ecu could this be the issue? Can I test it? Do I just have to buy one and test it? Any advice would be appriciated.

[JVZ32]

Did u replace the fuel injector where the misfire is at?