I had some black plastic specs in my injection pump, i just wanted to ensure it isn't coming from the fuel tank. That is why I was considering adding a second filter with higher micron rating, but if i loss power by restricting the fuel flow I will probably stick with the stock setup. Also have vibration and a bit of a rough idle, only at idle and from what I have read from this forum, some users have had luck fixing this problem by changing to the spin on fuel filter. I have already pressure tested all the fuel lines and the stock filter base, but I have heard that it can still be the issue.