Hi,
I have a 2010 120 1.6 multijet, has 160k km and recently started having a very weird problem.
When accelerating, usually the 2nd and 3rd gear hesitates for very shortly ( less than a second ) when looses the power and recovers back immediately. When this happens there is a noise ( similar to a blow off valve) but the car doesn't have one ( at least none I am aware of)
The engine does smoke time to time and when it starts smoking, would drop mpg to 33, still pulls fine, however you can notice a slight lose of power.

Any help? Thanks!

Hi,

I'm no expert but based on my experience my first thought, as i was reading your post made me think fuel starvation, old blocked filter or fuel pump issue?

I have read about many clogging fuel filter problems related to cheap supermarket fuel for example Morrisons (and others that use Bio mix) Diesel has a percentage of BIO diesel in the mix and seems to effect the more sporty porfomance diesel engine behaviour and causing fuel filters to clogg up well before you would expect.
The AAor RAC (forgot which) posted a report about increased vehicle breakdown call outs due to clogged filters and pointed to the different quality of fuels as the cause of the problem.

Then you mentioned engine smoking and loss of power.. so...for me that would point to a Turbo failure.
If you get a big puff of white smoke when first starting up then I would say the turbo is finished or on the way out.

Or could possibly be the EGR valve.. I had both on the wifes 1.9 renault diesel which went through engine oil quicker than I could go through pints of lager.

Have you checked your engine oil level recently?

hope that helps.

I suspect that smoking and high consumption is due to a regen but I don't think it should really smoke when this happens, on my 2.0 I can't really tell when it when it regens. Is it used on a lot of short urban journeys?

Seems like a leaking turbo hose to me.
Inspect them for (small) cracks.

+1 leaking pipe, or a pipe not attached properly.

had the same issue when i forgot to connect a pipe after a service (1.4t jet) but with no smoke

I think this might be your problem:

https://www.fiatforum.com/bravo/346277-2009-2-0-165mjet-diesel-boost-issues.html