My partner owns a ford fiesta 53 plate had it for 8 years and we seem to have a problem with the spark plugs when it rains. The car judders and miss fires when rain water has gotten in to the spark plugs then causes the engine light to come on is this a standard problem with the older fiestas or is there something else wrong. Any advice would be appreciated thanks 

It's twenty years old now, so just like us humans things wear out.

When was the last time it had a new coil pack and HT leads ?

19 hours ago, unofix said:

It's twenty years old now, so just like us humans things wear out.

When was the last time it had a new coil pack and HT leads ?

Couple months ago but it’s the only problem we have with the car it’s weird he’s change them the car will be fine for a few months then we get rain again and they play up 

A cover like this would help to keep the rain from getting into the sparkplug area.

https://www.ebay.co.uk/itm/203972430730?hash=item2f7db44b8a:g:qS0AAOSwVGBilKnk&amdata=enc%3AAQAIAAAA0JJ4CRZD%2BBl0mgWiNuNuB5g1ZkWjtj25rz21OinjzU72Pw01yv8iUqL1xy1JElDpQwgYdfLRNqp0wNjSlyuy83041wgcsf9tqiJScu3bQ0ydw7LwFugxQsqyF%2B1iEW5hJ1PZMEl8WvgvBUOGPJqPMVSLruP94TYUKKoLx79CiTW%2FsgERuKKQjy0O8%2FiLziVLRNwC5rr%2BrWn1uwq4jrdvrqmd223SI6bjr%2Fu%2BsFLrsf8J3bM6xQBn%2Bq5JVr1BgUpCrhiBaPfZNa0wx%2B3P2ScV0MY%3D|tkp%3ABk9SR-rmvK33Yg

He’s got one of those already on the car we think it’s where the rain goes through the jetters 

Is the rubber seal still fitted across the back of the engine bay?

Also does he use the screenwash more after rain?  The usual issue is the screenwash jets leaking.  I'm struggling to see how large amounts of rain could get to the plugs so thinking it might be a coincidence.

The core plugs often leak on these as well, but again shouldn't be affected by rain.

53 minutes ago, TomsFocus said:

Is the rubber seal still fitted across the back of the engine bay?

Also does he use the screenwash more after rain?  The usual issue is the screenwash jets leaking.  I'm struggling to see how large amounts of rain could get to the plugs so thinking it might be a coincidence.

The core plugs often leak on these as well, but again shouldn't be affected by rain.

He just checked all that and said it’s all fine