I got the car repaired about a month ago after it died on the side of the road from a leak in the intake gasket. During his repair he cleaned the engine. Hoewver, ever since this happened my car has been having a difficulty starting. It shakes uncontrollably and revs itself multiple times up to 3rpm. Today the check engine light started flashing and the coolant light came on (despite the fact that when I check the coolant resevoir, there was plenty in there). What could be wrong?