Hi,
It seems to have happened (got worse) since I lost the screw in gas cap and replaced it with a push fit one. I've cleaned the EGR (even tried blanking it off) cleaned the Maf, replaced the tps and iac. There's a high pitched whistling sound coming from somewhere which I'm thinking is air rushing in ... gaskets or vaccuum leak. the only other thing I can think is it might be the fuel pressure regulator.. Might replace that with one of these:

http://www.ebay.co.uk/itm/UNIVERSAL-...item53e8e3881d

What do you think?