Hey everyone. So I have a 2007 cobalt, manual 2.2 with 55k miles. I have an engine noise coming from driver side, back side of the engine. At least that's the location I can tell from inside the car. I have replaced the Timing chain tensioner. I took the cam cover off and checked chain is tight. I thought that might be the issue. I charged my ac system a few months ago, because it wasn't cold. After I charged it I noticed I started getting a humming noise when the AC was on. It wasn't loud until recently. Then about a month ago, I noticed this noise, it is only when I accelerate, mid and wot. It makes this sound, if I easily accelerate I don't get the sound. It sounds like a spitting/ticking/grinding noise. I have no lose of power, car still accelerates hard, there is no knocking or anything else. It doesn't make the sound when down shifting, only when I am on the gas pedal. I smell fuel but my guess it's the plastic connecters that crack I haven't replaced them yet. What could this be. I am hoping it is minor, This is my only vehicle if it breaks I am up the creek. So if anyone can help please. I am at my limit with this thing. I want to set it on fire let it burn and then call my insurance company.