I have a 2.3L 2004 ranger. I am planning on buying it from a good friend but lately I noticed, what I call it, a rod knock. It doesn't do it when I first start it but a few minutes after it has been running, I start hearing it. It is most noticable when it is idling and you just feather the throttle. I had a mechanic look at it and the first thing he did was take off the serpentine belt. We didn't hear ther noise. He thought it might be an accessory making noise. I put the belt back on and the noise was back. I have been driving the truck and decided to take to a dealership. I had them listen to it and at first it wouldn't make the noise but then it started again. They thought it was something internal. I notice the noise the most when I just start to roll and I let out the cluch. Just today I took the belt off again and let it warm up to almost overheating. no noise!! How can a noise like that come and go??
Anybody out there have any ideas??