This is a known issue with our cars. There is a leaky seal in the booster that releases pressure, causing the pump to repressurize more frequently. I have the same symptom. Eventually, the pump runs all the time until it burns itself up. Depending on which pump assembly you have, you may be able to have some of the work done by a dealer under a lifetime warranty. Otherwise, you'll have to suck it up and pay to replace the pump with a newer unit that does not have this problem. More details are at http://www.allpar.com/fix/ABS.html. -- David '91 K-Imperial