Check out http://www.boltdepot.com/fastener-information/Default.aspx - all you wanted to about bolts and nuts is in here.

The following page - http://www.boltdepot.com/fastener-information/Printable-Metric-Thread-Gauge.pdf - has images of various metric thread pitches. When you print it, the images are printed to scale. So you can very easily compare your bolt's thread pitch with the print out.

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1986 300E (3/2002) Rear ended and totaled (10/2009)
2000 Xterra (5/2000)
1992 400E (11/2009) -Sold
1986 300E (12/2009) - Sold
2004 E500 Wagon (6/2013) - Sold