My 300-6 seems like it has a slight miss at 1,500 RPM's is there anything I can do to stop it? I have 140,000 miles on the engine.

 

These motors never seem to run exactly perfect, sometimes they do. I thought I had mine running perfectly, got stuck in a huge traffic jam for over an hour (stop and go 5 ft). Its started running rough, the A/C pulled the idle RPMS down to 500 and I thought it would die a bunch of times, now its running rough. I bet it runs good again without touching it.