My tcs has just been on a 200 mile trip mostly of motorway driving at about 65mph. I was constantly correcting the steering in very tiny increments. Typically on a straight/slightly off straight road,the car would start to veer off,I would correct it but shortly after I would need to re correct. My federal car is all standard, good tyres and no obvious play in the steering rack or steering joints. The only thing I can think of was I over inflated the tyres.