Which one of the Engineers is right?

A mechanical engineer, an electrical engineer and a software engineer

are travelling in an old Fiat 500 

when all of the sudden the car backfires and comes to a halt.
  
  The mechanical engineer says
 "Ah! It's probably a problem with the valves, or the piston!".
  
  The electrical engineer says 
"Nonsense! It's most probably a problem with the spark plugs or the battery!".
  
  The software engineer says "How about we all get out of the car,
 and get back in again, It might work...".