Have you tried using WPS to do a compression test with engine running in miss firing cylinder.
1st link shows good cylinder
http://i1111.photobucket.com/albums/h474/madiagnostics/cylindercompressioncyl1gif-1.gif
2nd shows broken exhaust camshaft
http://i1111.photobucket.com/albums/h474/madiagnostics/Cylindercompressioncyl4gif.gif
HTH
David
Copyright © uk autotalk