Ford Focus 2009 P0300 multiple misfire rusty ground

Car was running great with an intermittent problem. These things are difficult to diagnose as a DIYer. Every now and then there would be a misfire, mainly when the weather was wet and damp.

[@JFSR_777]

Please try to show the issues before diagnosis otherwise great informative videos keep it up pal.

[@JFSR_777]

Also an update after a fix would be great thank you.

[@drivewaydiyer6504]

I do try with a lot of videos, but sometimes the work is on the go and then I get a result and I think it’s worth sharing. Thanks for the feedback though.

[@drivewaydiyer6504]

As it stands the car is running great and no issues. We bought the car in the middle of the horrendous rain and damp weather, but it’s been dry and cold since the fix. Hopefully it won’t be a damp related issue.

[@JFSR_777]

@@drivewaydiyer6504understood cheers pal. I've got a transit that dies/shuts itself off completely from time to time I've added an extra ground from battery straight to chassis however it's still doing it next protocol clean up the original grounds and see if that makes a difference.

[@drivewaydiyer6504]

Is it petrol or diesel? Could be a fuel related issue?