I found my way here but warning, I am not a mechanic. Son was driving 4X2, manual down the highway. It started to lose power. He pulled off. It was low on oil but not dry. He drove it around the parking lot and it just kept losing power until it was all gone. Had it towed home. It's in the driveway. Starts and idles great. No white smoke. Never got hot but will not move. It has 154,000 on it. Had a guy look at it and he said it could be the clutch, or the tranny and definitely a plugged catalytic converter(why would this have anything to do with power?). Deciding whether to send it to the boneyard or fix it. Guy did get under the engine while I put the clutch in and said "something" was working (slave?, master cylinder?? Heck I don't know) I like the truck.Want to keep it but am afraid to dive in to more repairs than it is worth. Has anyone an idea why it would just lose power while driving the interstate? This does not sound like a clutch problem to me Thanks for any thoughts you may have.

 

Yes plugged exhaust will make engine lose power at higher RPMs but idle would be OK.
No old exhaust out means no new fuel in..........so no power.
If the Cat converter collapsed internally then you would start to lose power at that time and it would steadily get worse.

Remove cat converter and start engine, see if power is back.
It is a $2,500 Federal fine to operate a vehicle on the road without a Cat converter, just FYI


"Will not move"?
So you can not even roll it?

Was it tow on a flatbed or just lifted at the front and towed?

Jack up 1 rear wheel and see if you can turn it

 

Thanks for info. Sound like catalytic converter is definitely involved. It was towed on a flat bed. I just jacked up one side of the truck, and tire spins freely. Also, there is a small exhaust leak. Could this contribute to a plugged catalytic converter?

 

Did the driveshaft turn when you did this?

When you combine gasoline("H"ydrocarbon) and air("O"xygen) and then ignite it one of the by-products is H2O(water).
Cat Converter adds to this by the oxidation of hydrocarbons into carbon dioxide and water.
This is why you often see water dripping from a tail pipe.

And this is why exhaust system rust out, from the inside out, lol.

So yes, a rust hole in the exhaust system would mean the rest of the system is probably close to rusting out, including the inside of a Cat converter.

Mechanics often remove the O2 sensors on the exhaust manifolds/pipes and then start engine, if it runs better then exhaust(farther back) is clogged.

 

I did not notice if the drive shaft turned. The guy who looked at the truck wrote down clutch, disc,pressure plate, bearing...and told me then I could find out if the tranny was ok after that. Just trying to decide what's right. My son did not have any trouble shifting when he was losing power. It was just gradual loss of power until nothing left. Maybe it needs catalytic converter, muffler for exhaust leak and the clutch? If the drive shaft turns when I spin the wheel, does that give me a clue about the tranny?

 

Means differential and output shaft on tranny are OK assuming you are in Neutral :)

But not a big deal if it shifted OK.

If it starts then fuel pump is OK.
Can you REV the engine or does it seem limited and start to stall out?
If it seems limited then could be clogged exhaust or Fuel filter.
Fuel Filter is $10 and not to hard to change, it is in the frame rail under drivers seat area, my '94 used clips on the fuel lines that can be pulled out with a flat blade screw driver.
The power box in the engine compartment will have a Fuel Pump(FP) Fuse, pull out this fuse, then start the engine, engine will die in a few seconds, turn key off, you should now have no or very little fuel pressure, so safe to remove fuel lines from fuel filter.

Can you shift it to any gear, including reverse, with engine idling?
If not then, yes, you have a clutch issue.