First post here, please treat me gently!
I've been asked to look at a petrol A-Class Mercedes (A160) for a friend.
The check engine light is on and it's running very rough, feels like only 3 cylinders.
I've had a quick shufty under the bonnet and I'm not even sure how to get to, or even see the plugs! (Bit of a modern car for me).
There's no Haynes BOL available, but I did find a "Peter Russek" manual which I have ordered.
I've had a quick google but nothing obvious has come up as to where to check first. Does anyone have a suggestion where I can start while I'm waiting for the manual?
TIA