Please help !! Bought the Mrs a td4 freelander 2003 to take away to uni. She's having a strange problem, the car keeps running after switching off the ignition (only a few seconds). The management light is coming on and is harder to start. Could anyone possibly help and offer an explaination plus rough costs etc. many thanks indeed !

I have a tropicalised 03 td4 that has a turbo timer fitted 8 second delay when switching of ignition the managment light is on while this happens

It never used to do this and has just started. It's also getting harder to start and will occasionally shudder when sat still with the engine on. Worried it's not going to start one morning and leave her stranded.