couple weeks ago my idle began to drop to 800rpm and judder a little, then rise to 1200rpm and back down, this was only happening at odd intervals while driving. Last couple of days idle has increased to 2000rpm on the odd occasion, after checking under the bonnet I found a hissing noise like air escaping. It seems to be coming from the crankcase breather, would this be causing the problem? Just wondering if anybody has had a similar experience? Thanks
