Hi,
I have a 2013 Volvo S60, T5 car and it gave me an error message while on the freeway going 70mph to slow down/reduce speed or shift up and start shaking really badly with the check Engine light. It shakes in idle too.

 

Check engine light is on. This means that you will have codes in the systems. Get the codes read. They are likely misfire codes.

 

yep.. sounds like a misfire - most likely cause is a coil gone bad, particularly if the car seems to run normal when you are light on the gas. You can borrow a code reader from an Autozone or find a friendly shop who'll scan the codes for free. Takes all of 10 minutes. All you do is plug the code reader into the port that's usually under the dash - kind of looks like an old school printer port on a computer. pop on the code reader, turn the key to position 2 (no need to start - just get the dash lights on) and the reader menu will guide you. Misfire codes will b P0300 (generic/multiple) P0301 (misfire, cylinder 1).... P0305 (misfire cylinder 5). If you have a single cylinder misfire, time to get a new coil :-)