I was thinking you might be thinking of them GM engines that can't take the idle as the
oil pressure drops so low. A Ford has more
oil pressure at idle. If you have 20 PSIG
oil pressure that would be fine for an engine at idle. Sure, I wouldn't idle an engine for an hour, but a few miunutes at a light or even 15 minutes can't hurt anything as long as you have good oil pressure. But really, what do I know....