2000 Buick Century Custom Mystery

My Century randomly will not start, I turn the key and there is no noise. The electrical stuff comes on, but it won’t start. I shift from P to N and try to start it and repeat for up to 5 minutes, of shifting and turning the key. I have gotten it to start in both P and N, while the problem has occured. I have had it in 4 times and no one can give me an answer as to what to do. They have said that it could be the starter or ignition switch. I think it could be the neutral safety switch. I am at a loss as to what to do. The car has gone a month without the problem occuring, but then the other day it acted up again. Do I start replacing parts and seeing if that works?

Something that I and others have been writing a lot about is the pre-disposition for GM Delco batterys to leak acid at the postive terminal,production model year 2000 was included in the group of batterys that have this problem, so once again I must say check the battery terminals for cleanliness and tightness before moving further in the diagnostic process, I would think that in 2008 the battery problem has been fixed,but I have been out of the loop for 5+ years now.

I have a 2000 Buick LeSabre. I have a similar problem to 200 Buick Century Custom Mystery but this car won’t shift when it is not running. It has started without any issue for about eight weeks. This morning it went ‘click’ and then a whooshing sound started coming from the area around the starter. Every time I open the car door the intermittent whooshing sound occurs. Does anyone have any idea what that could be? What did you do with the Century?