My fuel pressure regulator is not noticeably leaking through the vent hose (the one that looks like a vacuum hose). However is it still possible it's causing me a problem? Does anyone know the test steps for it?

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190E's:
2.5-16v 1990 90,000m Astral Silver
2.0E 8v 1986 107,000m Black 2nd owner
http://www.maylane.demon.co.uk/190esmall.jpghttp://www.maylane.demon.co.uk/190esmall2.jpg