ok-I know NOTHING about diesels. I was running the truck up to my parents today w/my son & it started running rough. I checked the air filter-looks good, indicator shows that its almost new. I'm standin here scratchin my head wondering.... so I thought I'd ask the experts.

 

oh-its a 96 f250 if that helps....

 

mileage, year would help, start off with the basics, check the fuel filter and make sure its a good color and not black and gross looking, that could be a simple problem right there, does it do it at all rpms? just sometime like when just starting up cold then smooth when warm or rough when warm and smooth when cold, the more details the more help you can get, the guys on here are experts and know more than half the dimwits at dealers and shops know!

 

96 f250w/204k on it.
Runs alil ruff when cold. Runs down right ruff when warm. When I get on the gas the whole truck would shake. Low rpms you could feel a shimmy or shake, on the throttle it felt like the truck was gonna vibrate of the road. I knowthe difference between suspen & motor-definatly motor.
Horrible ride home.

 

do you have access to any type of good scanners? a cylinder contribution test will be a decent start, the test fires each injector individually and you can listen if each one is mechanically sound

 

First change the fuel filter if it has been awhile, and while in there clean the FPR (fuel pressure regulator) screen.
It is in a small 1/4" size hole on the drivers side, inside of the fuel filter bowl, near the top. Get a Q-tip and remove the cotton from one end and use it to scrape that screen off till it is clean. You can also remove the FPR and get to the screen better that way, just don't drop any parts in the valley of death.

Next I would look at the wiring harness where it goes into the valve cover. There are two places on each VC. Check to see if they are burnt or melted. Also look for rubbing where it may have rubbed thru. You can also remove the VC's and look at the UVCH (under valve cover harness). Inspect it for rubbing or melted wires.

Is the air filter clean?

Is the oil old or low? Bad or old oil will cause alot of funny problems.

Could the catalytic conver be plugged?

Is this a stock truck? ie: still has the factory exhaust and intake filter box.

Have you had any maintenance done on it lately?

The more info you have on this truck the better we will be able to help you. A good explanation on how it feels when it runs rough will help too. I know it vibrates is it a fast vibration, does it get quicker when you rev the motor.

What type trans do you have, auto or manual?

If it is a manual it could be you flywheel. They are dual mass flywheels (DMF). The bearings in them wear out and get unbalanced.




Also WELCOME to FTE you have come to the right place to fix that truck. Before you know it you wil be racing that truck if you stick around here.

 

X2 on the above stated UVC harness. But also a bunch of other possibilities. And do you have a check engine light on?

 

Ok. 2day I changed the fuel filter. Still runnin ruff-worse acually, before I change the filter I started it up & it ran ruff. I went to drive it & it barely moved. Hardly any power. So I changed the filter-no change. The air box has hood flow-new filter as of dec. No engine check light. My dad thinks it's the timing-but like me knows nothing about diesels. I don't have acess to scanning devices. I'll poke around somemore. My truck is really clean, I got it in dec and haven't had any problems w/it.

 

did it slowly start runing ruff or did it just all of sudden run ruff like something quit working?

 

slowly

 

i think mine has that some problem

 

As of 8pm tonight, I moved the truck 60 feet to park it outside my garage. It ran REALLY ruff-barely any power. So as soon as it starts it idles ruff, put it in 'D' & go and it shimmies & shakes and 1/2 the power.

 

hope one of you guys can help-I wont be on tomorrow (sunday) but will be back on monday. I have some free time this week and hope I get an answer that I can fix.

 

look for it for sale w/pics. I dont have the time & I'm going for full custody of my son. I love the truck but no one on here can help....

 

where did you post it for sale ?