My other half is about to buy a 2003 mustang gt with a 4.6l engine that has 75mm tb, 30# injectors, and a few other mods, but the car sometimes won’t start and just makes a humming noise from the module in the passenger fender and when it does start, it runs rough and smokes like it’s loading up. It’s drivable, but doesn’t have the power it should have. I don’t know much on these 4.6’s, so we need help. I did notice a vacuum leak or smog leak in the back of the motor/intake. It’s pushing air...

2003 mustang gt running rough