I think I have a problem with the throttle pedal/somewhere in the management system on my 172.
The car has only done 800 miles, the problem developed after a couple of hundred.
When cold (stone cold i.e. the first mile or so). The first few mm (past the usual bit of free play, that is) of throttle travel do nothing at all. Depress the pedal a bit more and the power comes in suddenly. At low speeds at very low throttle openings (say a steady 30mph, 3rd or 4th gear) the engine feels very nervous, as if someone is tap-dancing lightly on the pedal (sorry, can think of a better analagy).
Once the engine gets a bit of termperature into it everything smooths out nicely.
The only other thing I have noticed now I have finished the first 625 miles is that the last little bit of throttle pedal travel doesnt seem to do anything.
Apart from that the motor seems sweet. Fairly linear acceleration up to about 5,000, then a marked increase, harder note to the motor. Havent gone past 6,000 yet, and only use more than 4,000 occasionally - I want to let the motor bed in a little more first.