Every now and then when I crank the car the starter will stick. If it cranks you can here it still turning I turn the key to off to try and stop it and nothing it just keeps on going had to unhook the battery to kill it. Only does this every now and then. I took the steering wheel off and took the key ignition out I didn't see anything out of the ordinary. Was wondering if this has ever happened to anyone on here before any help and advice is greatly appreciated.

Try swapping the starter relay with a good one.......

The starter relay may be getting stuck.

Are you talking about the silinoid on the starter itself or is there a relay mounted under the hood somewhere?

...the relay. It is in the engine compartment.

If the relay is good, the starter solenoid is below the intake manifold.

Ok thanks guys working night shift for the next three nights so won't get to work on it for a few but thanks for the help and I will update or ask more questions soon lol

I looked through the engine compartment and there is no starter relay mounted anywhere in there I traced the hot wire from the battery and it goes straight under the intake manifold so I will be removing that to access the starter and will go from there. But just wanted to let people know on the 98 deville there is no starter relay mounted in the engine compartment. I will keep this thread updated as I continue to tackle this issue in hopes of helping others out that run into the same thing thanks for all advice.

Youtube has helpful videos for the Caddy.

I have seen the starter relay listed in the engine compartment listed as CRANK in GM cars
You might check for that it would be a small relay in the engine compartment fuse box

It'* called the starter enable relay.....