Not long had my mk 1 172, noticed that tickover is a bit well, lumpy. Is that normal for the 172 or should they be smooth as silk? Its not long had a service with new plugs and filter, so that should all be fine and apart from tickover, it starts and seems to drives fine. Also Im getting 23MPG according to the OBC, driving is a mix of city and short full throttle dual carriageways only, but that still seems a tad extreme to me!? any ideas?