sluggish tranny when service engine soon lght on

i have a `90 gp le. my alternator failed last week so i changed it. while removing it i caused a spark because i did not disconnect the battery.(stupid me was late for work and changing in kragen parking lot) since then I am getting an intermittant service engine soon light on dash. when it is on transmission seems to act like it is slipping. when it is not on car runs fine. any clues to what may be causing this. I am attributing my recent car troubles to the 100k mile bug i am now at 100500 and troubles seem to be cascading now:dunno:

1st thing, get it scanned and see what is tripping the CEL. There is no point in speculating until we know what caused the CEL to come on.