I recently performed a tuneup consisting of plugs,wires,cap and rotor.Now the engine seems to shake like a vacuum leak,but i cant seem to find one.Do you think it could be the coil since i did not replace it.There are no codes except once an a while a o2 sensor code.It just seems like all the powers not there an sluggish.Its driving me crazy,i just dont want to keep throwing parts on it not knowing.