Car does not get used much but just over a week ago it developed a misfire after a trouble free 200 mile trip

Engine management light is on, restricted performance message flashing

Car did have a drained battery prior to the journey and is showing as fully charged now after two days on a trickle charger

I do not have access to a fault code reader so any suggestions - not sure on age of the plugs so I thought I would start with swapping them and I have a spare coil that I'd thought I'd try after changing each plug

Could a failing battery possibly cause a misfire?

 

Get the reader. Much cheaper than just one plug.

Don't guess the cause - it gets very costly very fast.

 

Any recommendations on a fault code reader for a 2002 S Type R

 

elm327 is cheap