Starting problem

[wah42251]

I have a 88 5.0 convertible and am having trouble starting the car. I've had the starter, battery and alternator tested, and all are in good working order. If I have the car jump started, it turns right over. As soon as I turn the car off, I have to wait 20 to 30 minutes before I can start the car again, but only after a lot of hesitation. Yesterday I had a loose battery terminal changed, and the car ran fine for the day, but this morning it was back to same problems. It almost seems that there is an open drain on the battery somewhere. (I don't know if this is related, but in January the display light on the radio (factory installed) went out. It came back on a few weeks ago. The last two times I used the radio, it appeared to have shut down while the car was off, I had to reset it twice in on day. I have the radio turned off and haven't used it in a week)

I would appreciate any help or opinions. Thanks.

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Wendy