Pontiac Repair: 2003 pontiac sunfire, air intake system, pontiac sunfire

Question
2 questions for 2003 Pontiac Sunfire (Manual)  1st heat/cool vents stuck on one position can't get defrost I know the switch tries it sometimes makes a funny noise but something is broken under dash. Is there any way I can fix this myself even if I could temporarily have only defrost that would be fine. (I live in MN )2nd question very general I know, but car randomly quits when slowing down or stopping doesn't matter if clutch in or out??? Pretty random,  Although more likely to happen if I stop fast. Sorry :( I am frustrated only 35,000 miles on car. I did store for all but 2 winters and did put stabil in tank I have changed fuel filter about a year ago and haven't stored since now drive all year round. Please help
Thank you SOOOOO much for your time ~Denise

Answer
Hi Denise:

the problem with the heater is a pretty common one there is a seal on one of the doors inside the dash that seal falls off and stick the ddor to the box and when you try chnage the modes on the heater control the cable that moves that door bends. It's really not a job you can do your self the top part of that dash board has to come off and the seal removed and replaced with a new one and then a new cable put on between the control head and the door. It's a pretty involved jobbut the parts are cheap. You'll have to pay more for the laob then the parts.. As for the stalling it could be just about anything.... I would look at possably a dirty throttle body/throttle plate or a idle control motor that is dirty or sticking. That is something you can do your self you just need to take the air intake system off the top of the engine and clean the throttle body and the plate. You need a can of carburator cleaner or air intake cleaner and that's all you need to do the job. It could be a lot of other things too but that is most basic possability I have for you.. Good luck :)