'97 4.0 power loss only at 55mph plus.

I am having a very intermittent problem. Every fifth time or so on the freeway at speeds of more than 55 mph I lose all power. When I pull over it will only rev to about 1300 rpm. I have to shut it off and sit for 10 to 15 minutes before I can start it and get back up to speed. It never dies, just loses power. This only happens at higher speeds. Sometimes in the rain, sometimes not.

It's a '97 4.0 liter automatic. 190,000 miles

Anyone have this problem?

I would say clogged catalytic converter. Especially with that many miles on it. Shake it (when your exhaust is cool) and see if it rattles. Same thing was happening on mine.

If the catalytic converter was plugged wouldn't it have no power at any time.

Everything is normal most of the time. I can drive around for hours on city streets and have no problems and then get on the freeway and it pukes.

I was leaning more towards a cps, tps or fuel pump.

Anyone else have any ideas?

Please.

I'm driving to Sacramento in a month and this would not be fun to deal with all the way there.

Thanks

Anyone have any (educated) guesses? This problem is killing me. Should I start with the tps, cps, fuel pump, anything else? I'm ready to start throwing parts at it but at around $100 each i'd like to know where people think I should start.

The cat conv sounds tight.

Anyone?

Please?

Sounds to me like it could be a clogged fuel filter. At slower speeds you don't use as much fuel so that why it becomes noticeble at higher speeds. See if you can take off your fuel line at the rail and then see if you have someone turn the ign. key on without cranking the engine. I don't know if it will work that way. But you should have good flow. If not you will have to drop your tank and pull the fuel pump to replace the filter. If you have a psi. gage check the fuel pressure.

I just had an idea. After taking off your fuel line. Before doing anything. Remove your gas cap, Then take an aircompressor blow gun and blow back through your fuel line. If the air can get through your fuel pump it might blow out the fuel filter.
Then take it for a test ride. (MAKE SURE YOU PUT A RAG OVER THE BLOW GUN AND FUEL LINE SO THAT GAS DOESN'T BLOW BACK INTO YOUR FACE. AND MAKE SURE THE ENGINE IS COOL.)

on my 2000 XJ (i dont know if its the same 97 up, someone chime in) there's no conventional fuel filter, rather there is a charcoal thing. its mounted to the floor underneath the vehicle basically a foot away from the pinion yoke for the rear end on the driver's side of the body.
my bet is on fuel pump.

Is the computer throwing any codes? I have a 97, and mine had similar symptoms with a bad O2 sensor.

Well, dynamite44 hit the nail on the head!!

The problem got really bad on Saturday. I could only drive about 5 minutes before it would lose power. It would stay running but if I pushed on the accelerator it would stumble. The longer I left it shut off the longer it would run.

Unfortunately for me I ran out of time trying to diagnose it. I towed it to the dealer this morning. They drove it around a bunch of times and it finally stranded the mechanic. Fuel pump is bad. Once in a while it is, anyway.

i had the same problem it was my cat.