hi i think ian has hit the nail on the head how ever after more time spent on it today i was scoping the map sensor i noticed the reading slightly high 1v ant idle and when misfiring 1.24v/1.35v was lucky to capture this due to it misfired for a very short moment and wouldn't do it again.
most annoying the customer has not given the go ahead to proceed due to lack of funds
fault code is p1553
there are no visible leaks (tested with smoke)