I've owned the same model since it was new and have not had these
problems. So let's get into it.
Starting with the ride, yes it's firm, too much so IMHO, but that's me,
so I suggest you check the tires' air pressure with a tire gauge and set
the pressures to those listed inside the fuel door. (IMHO these 3,650 lb
cars' tires are too wide, causing a too firm ride and quick steering.)
How many miles has your car done?
When was the fuel filter last changed?
You had the engine's air flow sensor repaired? or replaced?
When you drive it (up to 35 mph) what's happening? Is the transmission
in 2nd gear and the engine racing?
Or does the transmission shift normally but the engine lag - not
accelerate beyond a certain rpm?
Be patient, these problems can be sorted out.