My 1992 F250, 460+E4OD, 105K miles, has acted up a few times. It always starts, runs, and idles beautifully. Perfect emission test results. Three times now it has had a big loss of power on the road accompanied by a loud hissing noise from the undercarriage. I put my foot in it, engine sounds smooth, but bogs down, just no power. It barely makes 45mph up hills, and gets progressively worse... then a large silent puff of grey smoke comes out of it, the hissing stops, and everything is back to normal! Anyone experience this? Thoughts?


I haven't replaced/checked/fixed anything yet. Not much money to spend on it right now.


Thanks!

 

may be a clogged cat, or clogging cat.


try pulling codes and see if anything comes up.

 

Nothing on the codes. Still scratching my head. I'm hoping someone has experienced this same problem.

 

Clogged cat....check for excess heat at and after the cats. They can get super hot when clogged.

Good time for a new exhaust system.

 

Move to KY and get some straight pipes, or better yet, just run headers. It's a free-for-all down here and I love it! No emissions, no worries.

 

I had a clogged muffler do that with power but no hissing noise.

 

all my stuff is loud, but open headers or even a straight pipe (no turbo of course) is way too much for me, and anyone else listening.


if its gonna have open header, it better have some bite to go with the bark...

 

While he's got the pipes out, why not just throw a 470 in there...?

 

1+ for the clogged cat. Mine was doing the same thing a few weeks back, replaced the cat and new flowmaster cat back exhaust and the truck runs like new again.

 

Any luck with fixing this one? Mine is doing the same thing and I think it's a valve not the cat because it happens intermittently.

 

What valve do you think is the problem? If its intermittent then its probably not related to the CAT but fuel a delivery problem.

 

I hear a sound come from the egr valve when it's cold out and the engine is under load, like something popping. Then I lose power, and when I hit the throttle I hear a hissing noise come from the driver side. I pull over, kill the engine, fire it up and it generally goes away unless it's cold, around 38 degrees. Also happens when I hit a really hard bump.

Just drove 900 miles on it and it happened only under those conditions. Smooth roads and mild temps it was doing just fine.

I'm trying to pull codes the old fashioned way with a jumper wire and it's not giving me any unfortunately. I can hear the engine test starting with Engine Off but no flashes from the check engine light which is frustrating because i got it to work before.

I will try again to pull the codes.

 

EGR I think. I have a 7.5L and I hear a sound like something popping and then I hear a hissing on the passenger side and loss of power. I can baby it to safety and then restart the engine and it magically disappears.

Weird that it tends to happen when it's cold or I hit a nasty bump, the suspension is also really stiff.

Hoping I can pull codes tomorrow, tried to do the old fashioned method but it didn't work for some reason.