1998 Buick Riviera starts when it feels like it

We have a lovely 1998 Buick Riviera with less than 140,000 miles. Normally, it runs great but in the last year, it has developed a neurosis. When we try to start it, 98% of the time, it starts immediately. Once in awhile, you can place the key in the ignition, “click” and nothing. It’s as if the car were dead. Trying over and over is a waste of time. You have to wait about 5 minutes or so and WHAM! … it starts right away. Then it will continue to start fine for days and have a relapse. I can usually tell that it is about to happen because there will be a tiny (fraction of a second) gap between the moment we turn the key and the response. It will do this 4-5 times and then “play dead”. Wait 5 minutes and no problem. Then it will continue to run fine for days - even weeks. Our mechanic can’t figure it out. Can you help? Thanks!

I can usually tell that it is about to happen because there will be a tiny (fraction of a second) gap between the moment we turn the key and the response. It will do this 4-5 times and then “play dead”.

I’d need you to clarify this. First it seems like you’re saying that you turn the key and nothing happens. But here you refer to a “response” - and whatever the response is apparently happens 4-5 times before it will “play dead.”

So are you saying that sometimes the car just cranks & cranks & cranks but doesn’t start? And that then after a few attempts it won’t do anything? Or what?

When I get an older GM vehicle in with a starting issue the first thing I look at is the positive battery cable assembly.

The battery in your vehicle has the side mount battery terminals. And under the red rubber cover for the positive terminal corrosion can form that can cause a voltage drop to the power distribution center. So when you go to start the engine, not only do you have a voltage drop to the power distribution center, but you also have a voltage drop to the starter. So the engine doesn’t start. But if you keep trying to start the engine that voltage drop causes the positive connection to heat up where it eventually makes a connection and the engine starts.

Have someone remove both battery terminals, and on the positive battery terminal peel back the red rubber cover to expose the battery connections. If there’s found a lot corrosion under this red rubber cover, replace the positive battery cable assembly.

Tester

I’m gonna put my money on a bad starter. The next time it happens, hopefully you have someone with you who can tap the starter solenoid with a screwdriver handle while you hold the key in the start position.