My sons 2008 2.2 i-cdti Honda CRV has a intermittent problem in that sometimes he sets off and whilst driving the throttle becomes unresponsive. He pulls in and exercises it and eventually the response returns. I have just replaced all the filters and eng oil, which were long past their sell by date, and he reckons generally it is running better and getting better fuel consumption. This defect is sporadic and sometimes it works OK for ages. No messages or warnings generated. Any thoughts will be welcome.