Saab: Starting Problems and Fumes, plymouth acclaim, key cylinder

Question
Hi, I have a 1994 Plymouth Acclaim.  I realize this isn't in your Category, but I was hoping that you could help me out anyway.  If you can't, I will understand.  For the past 2 years, occassionally when I try to start the car, I hear just 1 click under the hood and the car won't start.  Sometimes it will then start on the 2nd or 3rd try and sometimes it won't start after 50 tries.  Sometimes I have to wait a few hours before it starts.  It doesn't seem to matter if the car is cold or hot.  Then once it does start, it is usually fine for a few weeks and it happens again.  I have recently replaced the battery, Alternator and the Starter, but it still happens.  Could it be the ignition switch? 95% of the time, you can't turn the key backwards to turn on the accessories so I don't know if there is a problem with the switch.  Also, there is a transparent circle around the key cylinder which is supposed to light up when you put the key in.  It only lights up if I bang it with my hand very hard.  Could it be a coil or relay somewhere?  Can you please give me some suggestions as to what it could be?

Also, about 3 weeks ago I started to get a really bad smell in the car.  It smells like exhaust fumes, and you notice it the most when the car is sitting still idling and you have the vent on.  When you are moving you don't smell it as much.  I popped the hood one day and I could smell the fumes.  I think the vent is pulling them into the car from under the hood.  My local garage said they found a bag somewhere and removed it, 2 weeks ago, but the smell is still very strong.  It doesn't smell like a plastic bag smell becuase I know what that smells like.  I brought the car to Midas, but they said the exhaust system looks fine.  Can you give me an idea of what it might be?  Could it be the Catalyst converter?  Someone told me that you can't tell when they are going bad because they break down from the inside to the outside.

I know these are long questions, but I would appreciate if you could give me advice.  I have already spent a lot of money and the fumes are very bad.  Thank you for you time!!!

Answer
Your starting problem sounds like a poor electrical connection, possibly a bad ground at the engine block or a corroded terminal at the battery. Certainly, the ignition switch itself could be faulty as well. As far as the smell goes, that's very hard to diagnose via my keyboard....make sure your heater core is not leaking...