Wierd situation. I am not a diesel god, so I am learning a lot about these things to date. I had my 8 injectors replaced at 38k. Truck is a 03 GMC. I noticed after pulling out from the Sunoco on the Ohio turnpike that I had a significant "knock" as if spark knock on the drivers side at about 2200 rpms at medium acceleration(coming on to highway off ramp). I let out a little and there is no noise. I must stress it is not mechanical valve train noise. Anyways, at times when there is no trailer, I get the same noise when I am accelerating and it always starts at about 1800 RPM up to 2200. There are days it does not do it at all, sometimes for days. It only does it when engine is at full temp. Any ideas??
P.S. I have tried every different fuel out there too. They all react the same.