Oh boy...talk about coincidence....just returned from Florida and
encountered the same problem in my 97 Grand Cherokee LTD (4.0/6cyl). After 6
hours of 70 to 80MPH the car lost power and slowed to 40 MPH. After turning
the car off, we could ride for 30-40 minutes before a recurrence. An
appointment with 5-star Jeep Dealer in Tampa showed no computer error. We
also thought it was a bad tank of gasoline as the symptoms subsided during
the stay in FL. Once again it happened 5 1/2 hours into the return trip and
then again every 1/2 hour after that. Upon returning home, my Jeep dealer
checked it out and guess what...he found nothing. That's where we stand
now..........waiting for another occurance. The dealer agrees with me when I
said it's probably the fuel pump overheating and then shutting down......and
they will replace it under warranty if it should act up again.

By the way......as we got back up into the cooler weather here in CT, the
problem stopped leading me to believe it is an overheated part.

> Hi y'all,
>
> I have a '97 TJ Sport (4.0L/6 cyl) with 90K on it. Pretty much stock
> except 30" tires. Last weekend while driving on the highway at 60-70
> mph, the engine suddenly lost power and it dropped to 40 mph and
> wouldn't go up. I managed to pull off, popped open the hood, but
> nothing seemed obviously wrong. So I restarted, drove all the way home
> without any problem. I changed oil and spark plugs and wires. Then the
> same deal happened again this week, it dropped from 60 mph to below 40
> mph, so I downshifted and after a few long seconds the engine came
> back. I don't know when it's gonna happen next time but it's pretty
> scary when it does. I also have the "Check Engine" light on, I did the
> on-off-on thing it shows code 12. Mabye I am just imagining it, but
> the engine feels sluggish and seems to be shaking more than usual.
>
> So I am just wondering if any of you have had similar problem with
> your TJ? I'll put in a can of those fuel system cleaners next time I
> fill up. Anything else I should try?
>
> Thanks!
>
> Rong
>