Jimm 2/10/2013Recheck the spark plug gap settings - as first step. Make sure the fuel and air filters are clean / new. Clean out the throttle body and mass air flow sensors.
HouseCallAuto 2/10/2013Read fault codes with a code reader. When an engine is running as terrible as yyou detail, the very first thing that has to be done is a check for fault codes. Codes tell a story and allow a trained mechanic to zero in on a cause without doing a half dozen unrelated things as a guess. If there are no codes after checking, tell me that on a repost. One thing to try (but do this ONLY after reading the codes) is to unplug the mass air flow sensor and see if the car runs much better with it unplugged. if it runs better unplugged then the sensor is likely no good. Also make sure the mass air flow sensor intake hose to the throttle body has no air leak.