I just completed a 1000 mile ride from Cape Cod, MA to Western NC. The truck, a 7.3 did a great job. Even got 19 MPG. The question I've got is...Under load, accelerating onto the highway, the whole truck shutters or skips. Not like it had a bad cylinder but more as if something was not in balance. It is not wheel balance and will stop if I take my foot out of it. Do injectors that are failing or what ever do stuff like this? The truck does have the power an early 97 7.3 should have and the turbo it working, I can hear it. I have not scanned it yet all I have is an OB2 scanner. Headed for Auto Zone to see if they can scan it for me.
Has anyone had something like this happen? I'd love to find a fix It drives me CRAZY!!!

 

AZ won't be able to scan it.

Automatic or manual transmission? 2WD or 4x4?

How old is the oil, and how's the oil level?

Have you checked the fuel filter?

 

15 qts Rotella 1500 miles ago
4x4
oil is not down
all new filters

It's been doing this since I got the truck in August. I've been searching for a fix. Thought it might be a center bearing

 

two possibilities i can think of, one is turbo surge, the other is a partially clogged injector. you might start by running some of this through the system;

Diesel Extreme - Hot Shot's Secret®?

you should be able to find a local vendor.

 

It's definatly not a serge it's more a vibration. I'll see if I can find some of that stuff

 

what speed is it occurring at? has the trans ever been serviced?
service interval for the transmission is every 30-35k miles.
"hunting"between third and overdrive or shuddering at around 40-45 miles in your trans telling you it needs the fluid and filter changed.
if the vibration is over 50 mph, i would look at the rear universal in the driveshaft.

 

It's throughout the power range from a stopped start all the way up to 80 as long as it's under a load. If I take my foot out of it at any point during that time it stops. I keep trying to come up with a better description of what it feels like here's the latest one... It feels as though there's a trailer on the back of the truck with a load. It would be that feel you feel of the trailer hitch weight bouncing on the rear of the truck.
I wish someone was closer so we could hook up and take a ride so somebody else would know what it feels like! I'm going to try to get over to Ford and see if they can scan it for some codes this week or early next week.

 

And I forgot... I mentioned earlier on all the filters have been changed.

 

I was going to say TC shudder until you mentioned its constant from stop to 80. I'd be looking at the driveshaft; U joints and carrier bearing. This past summer I was driving with a friend in his '98 Cummins on the highway. You can't hear much in the rattletrap, but I could feel this 'thrum'. I climbed underneath to find that nearly all of the needle bearings in the rear u joint were MIA.

 

is the check engine light on? if not don't bother going to ford because they will charge you for nothing.
no CEL, no readable codes.
try posting this down in the 94.5 to 97 powerstroke forum.
the guys down there are really smart.

 

Thanks! No lights on...I'll do as you suggest

 

That's actually not true. I've seen these Ford EEC-V ECUs (especially in the HD trucks) throw all kinds of codes without setting a check engine light. In fact, I just worked on an '01 SuperDuty that a multiple-cylinder misfire, and no CEL was set. The codes were there when you checked with the code reader though... Check engine light did work too...

 

So looks like I should go to the dealer either way... What's to loose? I'll go and hope I get some codes to post.
Thanks!!!

 

gas and diesel are different though. and a missfire code will not show up until it hits a certain number of misses. then it will turn the light on.
when i get a coil going out on the crown vic or 04 F350, i have to wait until it turns the CEL on before it will tell me what cylinder is the problem.

 

Is there a misfire code for the OBS PSD? I don't know what it could call a "misfire". The dealer should be able, however, to connect a device to the truck and monitor what each sensor is doing when the problem occurs. Monitoring and interpreting live input/output data will probably say more than a scan for codes. Depends on whether there's anybody at the dealership familiar enough with our trucks to know what to look for.