Hi Gents

I am having a similar problem to tthis gent below (found on another webpage).

The only difference for me is that the issue happens on the flat as well as on hills; you put your foot down, and the car is hesitant. Then when going through the gears, if you change into say 4th at 30-35mph the car hesitates and stutters, and if I put my foot down as if I was to accelerate hard it can sometimes feel like a major shuddering is going on. Then when the speed settles, it drives fine. It can be variable depending on the weather, if that helps.

"About 8 months ago my car had a service... new air filter, fuel filter, oil filter, spark plugs, oil etc etc etc....
Since then it stutters and hesitates during acceleration. Before the service I could be going up hill in 5th gear doing approx 30mph and no stutter or nothing. But now same hill, same speed but say 3 or 4th gear it now stutters... it is gradually getting worse"

The garage who did the service have test drive it and can find no fault, rather (un)surpisingly. I have tried two out of the four options below, which was the asnwer given from the other webpage; I always fill the car with top grade petrol, and have used various fuel injection/EGR valve cleaners when filling up. I also had the inlet manifold changed on 90k when the engine was replaced. Any other suggestions or help would be very much appreciated; apart form the stuttering and heistant nature mostly during acceleration, the car drives fine. No obvious noise changes. Answer from the other web page below:

It could be the coil pack, they are incredibly sensitive to damage if the engine is turned over with a plug lead disconnected - they generate such a high voltage without a plug to limit it, that the internal insulation breaks down.

It could also be a partial blockage in the fuel system, if changing the fuel filter disturbed some crud in the pipes. A tank of Premium unleaded (eg. V-Power) should help that, they contain fuel system cleaners. Or put a dose of fuel system cleaner additive through it..

Possibly the engine management system has not adjusted properly to the various changes.
Sometimes disconnecting the battery for an hour to clear the data in the system can improve performance. Only do this when you have chance to take it for a reasonable run (30 mins or 20 miles) immediately afterwards, so it can 'learn' the engine characteristics once it's fully up to temperature.

Another possibility, if it's an early Mk3 (up to about 2003 - 2004) or it's fairly high mileage anyway, is that the swirl plates in the inlet manifold are failing. The earlier design of these is renowned for failing, and there have been reports on the Mondeo forum that the revised type can also fail