I recently notice a muffled popping sound coming from my engine. I have an Injen CAI installed about a year ago and a grounding wire set also. No other upgrades, yet. I only notice it after driving around, and you can only hear it inside the car. It clearly is coming from the engine but when I have tried to find the cause inside the engine bay, I find nothing. Has anyone notice or heard of this??
Any help would be great, Thanks!