My Saab suddenly started shaking violently and lost power without warning a month ago. Went to local shop, had spark plugs replaced, happened again, code to replace throttle body, same issue a few days later. Towed to Saab certified shop, not throttle body code, but throttle pedal. They drove it for 100 miles, no issues. I got it back and the issue repeated 30 minutes later. Car runs but can only go 20 mph, engine shakes hard enough to rock car. Steering is tight. Already spent thousands, any ideas on what to do next? Thanks for any thoughts, car only has 21k mileage, perfect interior/exterior, can't justify sending him to Saab heaven!