I dont see how the fuel would cause this beacuse then every Z with this style injector in the area would have this problem. Sometimes when the car is off and when i am still around it i hear somethinig turn on that makes a humming sound for about 30+ seconds. Any idea what this could be? I was also doing a search and I found a post saying the ethonol causes the pintless style injectors to go out as well. How would i test the fuel pump just to make sure?