I haven't owned a 4 cylinder in a long time. So I bought my 2013 Dodge dart. 1.4 l. ITER Turbo and when I pop the hood or even with the hood down I hear a slight knocking like it sounds like it could be bad gas or something but I put premium gas and I also add octane booster to it. But I still hear noise from the top of the engine like the lifters are knocking a little bit. It's not loud. Might be normal but I'm not sure. Does anybody have any ideas?