I have a gentle thud thud thud thud thud noise that can be heard inside the cockpit with the best time to hear it when the vehicle is stopped. Can't ready hear it from up above when the hood is lifted due to injector noise but if you listen down in the drivers footwell you can. It's not there all the time but you do know when it is because the vehicle is nice a quiet from inside when it is not happening. Any ideas such as tensioner noise or ????