Hi

My Rangie has just passed the 400k mark and it's starting to feel a bit rough around the edges. I usually change oils every 10k but thinking it might need some more as change plugs about a year ago

As its on gas it's a bit more involved and has a bit more of a gas smell the usual.

So what I'm looking for is a guide or help on what to change and how to best tune it. I have done it mainly based on books and general knowledge but some help would be great on what to look at and what to look for

Cheers Dan