The other day I ran my 96 F350 very low on fuel and switched the tanks at the last minute. It sputtered and then caught back up and ran fine for about 150 miles. While driving it bogged down very hard, like it lost all power, and the check engine light came on. Pulled over, light went off, I checked everything under the hood, looked fine. Now today it is running horrible. I have changed the fuel filter and run a bottle of cleaner through it. Not helping. It starts fine, then sounds like it is gonna die. Very Low idel for about 30 seconds and then back to normal. And this cycle continues. I have worked on many 7.3's but have never seen this. Anyone have any ideas.

I appreciate anything you have.

 

Check the valve cover connections for loose or burned pins ,,,May also be the harness under the cover...When running bad ,unplug the connectiions to the covers one at a time ,the one that makes the least amount of difference in the way it runs ,,is the bad one

It could also have plugged one of the fuel lines ,,try blowing them out toward the tank ,with air ...

The code will help if you can retrive it ....

 

Try getting the codes. After checking the valve cover harness like Action said and all looks good you could take an IDM out of another truck (any buddies with a 7,3L?) and try it in yours. Mine just went out for the second time and it acted kind of like yours. let us know what you find.

 

Thanks for the feedback.

I checked the connections at the VC's and they looked fine. When it is running rough and i unplug both connections on the right side both nothing changes. If I unplug just one on the left it dies. However, when it smoothes out and runs right, and I unplug the right side it will die. So everything with the harness and connectors at the VC seems to be working. Checked the fuel lines and they were clean. Im gonna try to change out the IDM off my other 350 and check for a change.

Am I running out of options?

 

if nothign changed when you unplugged the right side then you most likely have some issues under the vc, time to ohm it out or remove for closer inspection

 

same thing happened to me a couple of weeks ago and it was the IDM. I could pull both VC plugs on teh left side and it didnt change at all. then sometimes it would run finefor about 30 sec then die. My IDM was like a fish tank. Im surprised it ran at all.

 

Running it that low on fuel it may picked some trash up....try cleaning the screen on the fpr.