Original post by: dancheripka ,
Sounds like they might have taken your plugs out to look at them and possibly damaged one or more in the process of checking. Might have cracked the porcelain or hit the head changing the gap. Another possibility is while cleaning your MAF sensor they might have touched the pins, getting oil, grease or dirt in the contacts. If its none of those are the culprit possibly look at your fuel filter, might need replaced.