I have a 2001 elantre it has 5 codes 4 tranny codes and one emmission code says small leak? anywho the car doesnt want to take off fast from a stop and if on a hill i have to put in low gear to start up the hill, but once moving goes like a bat out of ****? also when i first started off it shifted hard into 2nd then the engine light came on? going down the highway it seems to need to shift but dont! what could this be?