Coming in to winter I think the old Focus needs to be shown some love. It's very sluggish and juddery when accelerating and the MPG has dropped by about 5mpg (possibly partly down to colder weather) but I've had the car for 4 years now and there are certain things I have never done.

- Spark Plugs

- Replace Coolant/Anti Freeze

- Replace Coil pack

Are these all things I could do myself? I have a spark plug wrench so am I right in thinking its a simple undo and replace with new ones? With regards to the anti freeze I don't want to top it up I want to replace all of it as I'm currently not sure on the anti freeze:water ratio of the stuff thats in there as I've never so much as topped it up. Is this an easy job?

Any advice/Tips much appreciated.

Turned out to be spark plug 4 (closest to timing belt) was sat in a small puddle of oil. Cleaned it all off and done a long drive and working fine now. Aparently can be caused by vapours over x amount of years. Will still change spark plugs and renew coolant ready for the proper cold weather.

The 1.8 the air filter has also a small oil filter ul see a small square piece of foam if these arent renewed the oil vapour blows back and can cause that oil also the tube that connects from the head to airbox ul see it is worthwhile cleaning as is the pcv valve front of engine to the right just under the exhaust heatshield pull out and clean clean the hose and replace

Looks like the oil has returned, Only around spark plug 4 (nearest cam belt side). Any ideas?

Looks like the oil has returned, Only around spark plug 4 (nearest cam belt side). Any ideas?

cambelt side is plug 1 not 4 sounds like possible piston rings letting oil through