Why feel brake pedal hard sometimes ?( not after hard braking)
 

Sometimes I feel like brakes hardened even in a city traffic.It feels almost like I've stopped the engine and braking ( not this much of course, but it is very obvious)and brake pedal comes to normal softness after a min. or so .
Also ESP light came on and I will go to service.
But this brake problem was there way before the light .
Any help will be very appriciated.

No clue, but have you had your brake fluid level checked out?

Also, brake fluid is supposed to be changed at 20k no matter
 

how long you've had the car...make sure that was done...think you have over 20k on your car ;-)

Yes ,checked. Also it's still 18K km. in 1.5 years. Thank you.

Vacuum leak? It sounds like your brake booster is depleting or losing vacuum completely.
 

"Power brakes" use engine vacuum to increase the pedal force you apply. There is a check valve to prevent loss of the vacuum from the booster. If that leaks you should feel the pedal harden up as you hold it down. Remember, the engine is only producing intake manifold vacuum when NOT in a boost condition. Idle and closed throtle deceleration are highest vacuum conditions.

You could have a leak in the booster instead of the check valve. See the dealer about it in any case.

I noticed this the other night on my 2001 TTQC??
 

The pedal all of a sudden it felt very hard after its 'normal' softness. I have had other brake issues with the pedal going all the way to the floor and not coming back up in very cold weather. This problem has not been found or fixed by service and has occurred 3-4 times last winter. At the time I thought it was the brake booster perhaps this is another symptom of the same problem.

Denny did interval change I thought it was 2 years never did the coupe at 20K

D'oh ... posted that before my morning coffee and got it backwards...2 years is correct.

Great information. Thanks a lot.

Thank you. I'll ask to the dealer. I don't feel they'll find the problem though.
 

Your problem is much frightening. Pedal going all the way down is not a nice feeling. :-(