front brakes has "pulsating" feel whenever I brake. Is it due to warp rotors?

If the caliper is frozen you'll need to replace it. When you release the brake pedal the piston inside the caliper will not pull back and release the brake pads from the rotor. This may make your steering could pull to one side or at least ruin you fuel economy. Pedal pulse is caused from warped rotors or brake material bonded to the rotor. A good tech will use a dial indicator to see oif the inside and outside of the brake rotor is straight or true. If its not and there is enough rotor material you can machine them. Your brake pads should be okay if the tech scruffs them up with sandpaper. Good luck.