-don't know, but yesterday after I used jumper leads to start my car it was running rich as all hell, car had been sitting unstarted for probably 3 months, drove it around for about 1/2 hour and is still running like shit? - was perfect before. When I jump started it i had the other car turned off which can help avoid a power spike, it didn't have enough grunt to fire it up, so I then started the other car and let it run for a while, it then started fine.