I've only been a member here for a few days but I'm liking it alot.
I've had a problem with my '01 Ranger ever since I got it in '03 with 32k miles. It sounds like valve clatter to me. I took it to the dealer (under warranty) and of course, they said there was nothing they could do about it. At first, they refused to even acknowledge there was any noise at all which made me angry enough that I questioned their skill.
Super unleaded did alot for it but it still made some noise. The check engine light came on recently due to insufficient egr flow. After reading several threads here, my symptoms seem to be consistent with a bad dpfe sensor. I replaced it today (plastic) while changing the oil and not only do I no longer have the check engine light, it runs without the clatter.