Nothing as yet in the two short months of ownership. However the CV joints are a bit rattly now.
I bought the car from a dealer for £3000 with a full Ford service history covering the 129K. It was/is in immaculate condition and drove perfectly.
I love the sound of the V6, although it could do with a bit more power as it is a large car.
It is quicker than most things on the road, but its on the motorway that it really goes well.
The handling is not bad for a car its size, but I find it better on long sweeping a roads than tighter in town driving.
Although the cars great for a family with its size and comfort, I only really drive to and from work so it's a bit wasted. I'm now thinking about swapping it in for something smaller. I had a Golf GTI mk3 before so might go for the VR6, partly due to the fact that I miss the build quality as the Mondeo does have some rattles.
The car makes the renowned moosing noise now and then, which can be a bit embarrassing in an underground car park, but a bootful of right pedal usually sorts that out!!
It also has that hesitancy at the 3000-3500 rpm range, but found that if you accelerate smoothly instead of wanging your foot to the floor as fast a poss irons it out.
I would recommend one, but make sure you choose carefully avoiding lowered, chipped and blinged up models, which have been ragged.
You get a lot of car for your money, and it always puts a smile on your face under full bore acceleration!!
I have a 98 ST24 and it's a fantastic car. My review is in the 98 section and starts "the best car I've owned to date" if you want to read it for some information about the ST24. You can get an anti moose pipe from the mondeo enthusiasts group for around a tenner to stop that noise. I've got an induction kit (Stainless steel cone from Quickshift) but I've never had any moosing from it. The sound is great!.
The hesitation you talk about at 3500rpm, if that's accompanyed by more engine noise and less power then you might have a problem with your engine air shut off control (also known as the Inlet Manifold Runner Control box). This is a problem that affects the Mk2 V6's. I'm assuming yours is one. This box opens the secondaries on the throttle body when you go above around the 3500rpm mark. It maybe just that the cables sticking as you say re-applying the throttle slowly sorts it out, but it can be more serious. Its the heat that gets to the PCB (Printed Circuit Board) that can really kill it. It's the box under the plastic engine cover with Duratec V6 written on it if you want to have a look, check for dry joints. I've just replaced my box and it was £146 plus VAT!not including an hours labour, but the cars been restored to it's former glory. Enjoy the V6 mate, theres not much out there that handles this good and sounds so great.