In my previous car (E30 with M40 engine), I used to have a problem with the camshaft valve train. It needed to replace that and the car started to rev more than 4500. But the car was ideling at 700 RPMs, not 500 RPMs. It could be I guess...
best regards, Tony Sticks [url=http://www.bmwe36blog.com/]BMW E36 Blog[/url] / [url=http://www.bmwe36blog.com/forum/]BMW E36 Forum[/url]