On 31 Mar 2004 15:21:54 -0800, rco4567@yahoo.com (Rong Ou) wrote:

>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?

I had a similar problem on my '97 TJ. It turned out to be the
catalytic converter, and probably related to the common manifold
problem. Studs broke on the manifold, causing looseness, which
apparently shook the cat so much that it clogged up.