I have a 97 Grand Marquis.

I has an intermittent starting problem. It will be fine then out of the blue it will not turn over at all. I tried jumping it and it has a new battery. It seems to have full power. The lights don't dim when I try to start it.

If I let it sit for a while (1/2 hr or so) it seems to start after that. Then it will be fine for a while then do it again. My mechanic can't figure it out because when I bring it to him it is not having the problem. Please help!

Thanks

 

Just a guess but sounds like the starter motor brushes are getting hung up in their holders in a hot engine condition which is causing the motor from turning.

The next time it won't start when hot, try tapping the starter housing with a heavy metal object to see if you can free the brush(es) to reseat on the armature. If this works, the starter is at fault and a replacement is warrented or rebuilt with a new set of brushes.