Black Smoke

Hello.

I have V8, BJ 91 3.6. From a few days on, I see black smoke on the accelerator. First, I thought the probe Lambda was kaput. I changed probe 5 years ago and I have been about 70,000 kilometers but can be.
I found another information on the Internet - fuel pressure regulator.

So the question is. Should I buy new pressure regulator or the pressure regulator is OK. My V* was standing 233,000 km. I have no idea if the pressure regulator should be renewed.

Thanks for every tip, gruse from Poland.