My 98 has a problem with the delayed /intermitent(sp) wipers. After the wipers have been on for a while (20 + minutes), the motor seems to get "lost". It stops the wipers all over the windshield, except at the bottom. They were even stopping all the way up...... After I shut the wipers off, and wait a couple of minutes, they do ok, for a while. If I leave them on slow speed, no delay, they're fine... Is the wiper motor going bad..?? Some electrical glitch...??? How expensive is it to fix.???