Hi,

My 2008 2.0 Diesel is having some problems. For a year or so it has had a rough idle, which has got gradually worse. I think the idle speed is ok, but it vibrates a lot to the point where everything in the car rattles so I try to keep my foot slightly on the throttle to stop it. Above 1000rpm it is smoother and quieter, but I can still detect vibrations that don’t feel right. When accelerating it vibrates more noticeably but at a much higher frequency than at idle so it’s less noticeable.

Fuel economy has recently dropped a lot from about 43mpg to 38. It has had other potentially related issues – I replaced a very blocked fuel filter a while ago because it was stalling a few seconds after starting, which resolved the problem. More recently it has stalled a few times and needs to be turned over for a while to restart, but not often.

Currently I’m suspecting the injects may be dirty or faulty, does this seem reasonable? I’d appreciate any other ideas too!

Thanks,
Richard

Had similar probs on my '08 - the diesel knock was louder than normal - and the idle was rough. Treated it to a tankful of BP Premium diesel and a bottle of Comma 'Diesel Magic'. Halfway through the tankful and the knock has progressively quietened a lot - seems to get better every outing - and the idle is smooth and almost silent. I'll finish this tankful and take stock then - but all seems promising.

Generally much quieter, but sometimes quite noisy on start-up - give a brief spanking in 2nd gear - up to 4,500rpm - and everything quietens down beautifully.