Ok, so my i bought my 93 saturn sc2 with about 120k on it. i realized that the back up lights werent working and found the problem to be that the backup light switch was not plugged in. i plugged it in and started the car. when i started up the car and put it reverse it immediately reved low then stalled, sort of just died. also, the car stalled when i put my foot on the brake. so, i realized that the switch was probably unplugged for a reason and unplugged it again. i tried it again and the car didnt stall when i put it in reverse however, whenever i put my foot on the brake it revs low and die. when the car is idleing it idles rough and gives me smoke out the tail pipe, but it is not consistant. it might do it for 5 min then stop. it is also reving down while idleing, not a huge amount but enough to make it sound as though it is going to die. and every once in a while it will rev very high when no one is touching the gas.
this had never happened before i tried to fix the back up lights, and i am perplexed as to what it may be. also, a preexisting condition: when driving around 30 to 40 at a constant speed, the car stutters, sort of like a hesitation.
any help would be appreciated. i havnt taken it to a mechanic or anyone else yet considering its 9 oclock on the week end.