I have a 91 240sx HICAS with abs brakes. Lately after the cars been warmed up it feels like the brakes are dragging. The car starts slowing down and I kinda have to give it more gas. Also when coming to a light I don't have to apply the brakes very much in order to stop...at about 10 mph the car will stop by itself.
The only aftermarket addition I added to the brakes are cross drilled slotted rotors. For the first few months the brakes didn't feel like they were grabbing on their own. Now after I've been driving a while they do feel like they're grabbing. When I'm on the interstate is the worst because it's creating so much heat. When I get off I can smell the brakes almost burning. I've noticed that I lost a significant amount of pad in the rear brakes compared to the front. And even after I've parked from driving I look at the left rear caliper and it is actually smoking because it's so hot.
Today I replaced both rear calipers because my guess was they were sticking. So after I did I got on the interstate to see if they would grab. Felt like nothing was dragging. Then after I got off the interstate about 10-15 minutes of driving they started to drag again!

I've replaced the master cylinder, rotors, pads and now rear calipers. This is really aggravating not to mention is killing my gas mileage. Does anyone have any idea what else it could be?