I have a 2002 5.9l Durango. I have had difficult to diagnose intermittent engine issues for a couple of years. I might drive 40 miles with no problems and them the engine would hiccup, once, twice, or several times. Sometimes there would be no problem for a couple of weeks. I would do something that I thought might solve the problem and then a week later it re-appears. Ultimately the only possibility was the pcm. I bought a rebuilt pcm and it appears to have solved the problem. Here's my dilemma...they want me to give them the old pcm or pay a core charge. Previously, I would have liked to have a working pcm to plug in to troubleshoot the cause of the problem. I'm willing to pay the core charge if the pcm can be used to troubleshoot pcm problems in the future because it's totally functional with only minor occasional intermittent issues. The question is...If I need to put the old pcm back in to troubleshoot 10,000 miles down the line, will it fail to function because of the odometer discrepancy? Thanks for any insight.