I have a 2004 Chevy Impala with 100,000 miles. A couple of times in the last year the car just wouldn’t start. Everything comes on lights, radio, etc. but it doesn’t even try to turn over. I took it in twice and the mechanic of course couldn’t find anything and it didn’t happen again until recently. It has happened 6 times in the 3 weeks. It runs fine, has a new battery. Mechanic keeps telling me they can’t diagnose it until it happens when they have it. I have had it towed to them twice when it has happened and of course when they try to start it it starts beautifully. Mechanic is guessing it may be the starter but doesn’t want to assume. My dad said he heard a caller this past weekend on Car Talk with a similar problem and they were told it was the crankshaft position sensor and to not even mess with the starter. Any advice? This is getting very frustrating. Should I just have the crankshaft sensor replaced?
The next time this happens just shift to neutral and see if it starts. If it does then replace your neutral safety switch. You also need a new mechanic. This is a very common problem and is easily diagnosed by the description alone.
Take apart the battery connections. Clean them and put it back together. Might help, might not.
GM was having lots of problems with the ignition switches. Jiggling the key around when it won’t start usually would get it to work. If so, then replace the ignition switch.
A failed crank sensor will not stop the starter from working. Is the “security” light flashing when this occurs?