Hello and welcome to our web page here my name isXXXXX a Certified Volvo Car Expert Mechanic.I'm going to try to help you find the help you need
give me more details so you say when you have problem your car will not drive more than 20 mph?
also tell me how problem starts your drive car ? hot or cold engine ?
any dash warrnings come on ?
the more details how it happens it helps me better