Whenever I drive my 90CS I occasionally get a random loss of power. Doesn't matter if I'm accelerating hard or gently, it just suddenly doesn't want to go any faster even though I'm depressing the pedal. After 2-3 seconds power comes right back and the engine revs to 3-4k and starts pulling again. So far my best guess is a vacuum hose cracked somewhere or oxygen sensors needing replacing...any ideas?