yea i switched to 20w -50 car runs beautifully...be sure to check all vacumn lines also...i had a idle control vacumn line come off and the car would not move what so ever...maf could be your bet to make sure clip is scure , if not you'll be getting way to much air and u wont rev past 3k in any gear/..hope this helps this is what has happened to me since ive owned mine...

jason