I am at witts end here I had a hole in my oil pan and decided to replace the old one with a new one... I removed it and put the new one on and everything was running fine... drove it around for awhile and then let it sit for a bit.... still fine then I drove for about 40 minutes and now it won't start up! I got it to run two times since then but after it runs it dies as soon as I shut it off... I checked all the fuses and they're working,,, I don't here the starter clicking over instead when I have the key on the on position I hear a humming noise... what could this be?