I've had my 2009 1.0L IQ2 for 3 years, and in all this time it has been hesitant and jerky when pulling away from a standstill and has had a pretty bad acceleration flat spot between 2000 and 3000 rpm. One impact of this was I had to drop down to first gear on some steep hills, particularly near the start of a drive.
The car has been regularly serviced, so I assumed that either the clutch was starting to go or the flat spot was just something you had to live with.
I tried cleaning the MAP sensor and the PCV valve and even using Wynn's cleaner for O2/Lambda sensors, but it made little difference. Then after raising the problem on this forum, Andy (Ch299) walked me through a procedure for cleaning the aluminium plate that sits on the inlet manifold, which has small tubes that become blocked with carbon. Essentially, the early catalytic converters (up to mid 2010) took dirty (full of carbon particles) air and fed it via the aluminium plate into the EGR valve. Over time 2 of the 3 small tubes in the aluminium plate become blocked, and this has a devastating effect on the car's performance. In 2010 they changed the design of the cat to address the problem. Some dealers retro-fitted new cats, but with the age of the cars now, there's no chance of this any more.
The solution is to remove the plate, unblock the tubes and clean out all the carbon deposits. It's not a difficult job, but it takes time (0.5 - 1 day) and involves:
Removing the wiper assembly and the panel(s) beneath it
Removing the throttle body
Removing the intake manifold
Removing and cleaning the EGR valve
Cleaning the aluminium plate, and particularly unblocking the tubes on the first 2 cylinders
Installing new gaskets
Topping up coolant
The car then needs to relearn it's idle which takes a few minutes, with lots of clouds of vapour.
The total cost was only about £25 for the gaskets, a can of carb cleaner and some coolant fluid (total around £35), but the difference is amazing. The car pulls away smoothly now, and there is no flat spot at all. The performance is so much improved! The steep, slow hill I had to go up in first gear, I can happily do in 2nd now
The problem will eventually reoccur (but it should take a few years), and can only be fully resolved by fitting the new design of cat. These are available for around £200 with fitting kit and are reasonably easy to fit. I plan to do in the near future.
If you have a 2009 or early 2010 1.0L IQ and are experiencing any of the problems I detailed, give it a try.