When I bought my 08 plate Mondeo 2.2 tdci Titanium X I was surprised to find that on occasion there was a very slight hesitation when driving at 30 in 4 th and 40 in 5 th . I first I thought it was just me but later found that this was happening at exactly 1400 rpm and only when on very light throttle. I searched the Internet and found that others were experiencing the same problem, many had taken their cars to Ford under warranty, but there did not seem to be a fix, indeed one Ford dealer suggested driving in 3 rd in town to overcome the problem.

I eventually found a post that mentioned that Ford had modified the air filter for this model to overcome the issue (the later Mk4.5 has a redesigned air filter housing). Apparently there was a known issue with pressure drop at the MAF caused by the low speed of air exiting the air filter element. The part number for this revised air filter was AG91 9601 AA.

As my car had been serviced by Fords from new I assumed that my filter would have been replaced with an up to date one and when I checked I found that this was the case, it was a AG91 9601 AD. However, although it was not due for a change and was not particularly dirty I decided to change it anyway and amazingly the problem has gone away!

So if you are experiencing this problem it might just be that a filter replacement will resolve it for you.