Engine Management light on

[David Loft]

Before having a full service recently the car had a bit of an erratic idol at tick over. Had the service done, all filters, fuel filter, oils, spark plugs etc etc replaced. 
 

erratic idol still existed, after a couple of fuel injector cleaner solutions added to the fuel at full tanks, the engine management light came on. I have plugged the car in to a reader, only two codes came up one for a clutch sensor which was green but a lean fuel code came up, nothing else, no mass air flow sensor codes, or anything else, my mechanic wasn’t too worried and reset the E/M light. Half way home of a 200mile journey it come  back on again. 
 

now the start up is really laboured, 3 to 4 long turn overs be fore it fires up, and stop start journeys the car starts up straight away, but after an hour of non use the car goes back to the start up issues.  There is no smoke discharge at all, although now does smell a bit rich at first turn over. MPG Is way down as well from 32mpg to 22mpg. 
 

no miss fire codes or any other fault code available . 
 

can any one shed some light 

 

its the 1.8 turbo petrol engine 

[Steve Q]

It might need a diagnostic check with a more sophisticated diagnostic system, no disrespect to your code reader. 

Erratic idle as you've rightly suggested could be the maf sensor but also the lambda sensor, cam position sensor, crank sensor, injector or injector seal etc.