This report is for a 2004 Silverado with a Jasper remanufactured 5.3 engine, with 15,000 miles on it. Oil is being changed in the range of every 1500-2300 miles (3-4 months) using Formula Shell 5w-30 and an AC Delco PF46 filter. Despite of their several decades of experience in building engines... they claim that they don't understand why there is lead without copper, or why the lead continues to hover. They refuse to do much for me, without any other symptoms. They claim other things can cause high lead results... fuel additives (which I don't use), an engine oil cooler issue (which the truck has the same one that it left the factory with), and on and on. I spoke with them several months ago regarding this... and at that time, they insisted that I just continue to monitor the situation, and let them know if it continued or got worse. They've flat out refused to replace the engine under warranty based on this report, that they don't replace engines solely on UOA reports. There have to be other symptoms. They tell me that my concerns are documented, and not to be worried about the warranty. Speaking of the warranty... it is expiring in the next couple of months, they seem to simply want to get rid of me. This is my third Jasper engine in the same truck. The first Jasper engine had a collapsed lifter, and the second Jasper engine had a cracked head.