I was installing a new alternator after a week or two of the battery being dead and found this loose cable. I totally forgot where it hooked up to! My car runs but it's knocking at boost. I was ganna ask to reflash my tune, but this might be the issue instead! Please help if possible

 

Looks like a egr or evap solinoid plug is it still installed and functioning alot of people delete those.

 

Thats definitely the egr plug. Shouldn't cause any problems. If you still have your egr system you can plug it back in.

I have a very similar issue. Haven't figured it out yet, but i get alot of knock at boost at well. But i think it started before I replaced my alternator.

 

Thank goodness! EGR is gone on the car, so thanks everyone! Now to see why my car is knocking.. it's the strangest thing! The check engine light is usually on, but turned off after alternator. Maybe I just need to reflash my tune after all.. doesn't hurt to ask my tuner right? Please let me know if you find anything!!