I installed my 450's a while back and now I realize I'm getting bad gas mileage. The weird thing is that I don't seem to lose a lot of gas while driving, but when I let my car sit overnight, the next morning I have less gas, WTF? I am thinking its a leaky injector cause when I start my car after a while of it sitting, it smokes black. How do I check each injector to see if it's leacking? Thanks ahead

 

For some reason mine did the same thing but i dont think it was the injectors.I had a walbro which i'm guessing left enough pressure in the rail to make it do that.What do u consider bad gas mileage?