I agree with 700GT6, first make sure emergency brake cable isn't stuck, second, make sure caliper is working properly. Brake fluid will break down over time, but won't cause the problem you are discribing. You either have a hanging brake do to caliper, or shoe hanging, or if you use your emergency brake, it could be hanging. Fluid will make the whole system function poorly. Throttle bodies are always dirty with oil and such, doesn't hurt to clean it, but if it is running fine, well your choice, and forget about the tire fill. Make sure you use a good brake fluid rated above 400 degrees, no use putting back in the same stuff. If you want to beef up your brake system, change to a high performance pad, replace rubber brake lines with metal ones, and the rotors on these cars are as good as they get. Big and strong, but you can upgrade those as well if you like...good brake fluid will cost $40 or more, so don't skimp...