keep in mind next time you have an electrical issue to start small, fuses and all connections, alot of times elec problems are lookin at you right in your big ugly mug. dont feel bad either its happened to me but thats when i learned to start with the basics

 

LOL In nearly 50 years of wrenching on cars I have seen some pretty f'ed up things, but I can't remember one time that I, or anyone else that I know, has ever started a fire under their car while changing the oil.

 

In my defense the fire was due to the puddle of oil that had missed the drip pan. Scared me half to death when went off to the point that I had to pump myself up to get back in there and start again on the filter. But I'm glad I'm the first.

 

Are you sure you don't have a dead cylinder or 2? Should require more than a spark to set the oil on fire.