I have a 1.6 tdci Zetec S and it produces a puff black smoke if I try to accelerate too hard. Its doesn't need to be pedal to the floor to make it happen. When this happens there is also a lack of power like a bit of turbo lag. I've been suggested adding diesel system cleaner but some people say it doesn't help. The mechanic who suggested it checked the turbo and pipe work for cracks. After the lag in power there is no smoke and power is fine. Any suggestions or weather using cleaner is a good idea would be helpful. TIA

1. Cleaner won't do any harm, so I'd invest £5 in a bottle.

2. I had a similar symptoms , also on a 1.6 diesel, which was improved by cleaning the MAF sensor.  Actually, disconnecting the MAF sensor electrically helped, but gave a warning light on the dashboard. It's a 2 minute job to disconnect (well it was on my c-max) so you could try that and re-connect if no difference.

I'll give them a try thanks for your help.