Seems like a Misfire, Need help

[nosxx002]

I have a 99 F-350 with a 7.3 powerstroke and a 6 speed manual. I just bought it about 2 months ago and it was always running fine. The truck has 214,*** but only about 75,*** on a new motor and 15,*** on new trans. Now whenever I start it it throws out quite a bit of bluish smoke, and it sounds like its idling rough, kind of like a built up gas motor with an aggresive cam. When I get on the highway, it runs a little rough under load, and you can see bluish smoke in the mirrors, but then instantly it clears up, almost throws you back in your seat, and then theres no smoke anymore. It kind of goes off and on, so it makes me think its nothing too serious in the motor. Even when I have my big trailer on, its nothing steady, just on and off. I don't know much about these diesels or how to diagnose it myself, can't really afford the $$$ for the Ford dealer.

 

[Tail_Gunner]

Check the wire harness connectors under the valve cover (UVC). They are notorious for coming partially apart causing a intermittant miss or keeping glow plugs from working. Ford came out with some little plastic wedges for the UVC connectors that keep them from coming apart.

If you're going to lift the valve covers, it's be a shame to not put new glow plugs in unless it was recently already done.

 

[nosxx002]

I'll try that this week. Will I have to put new gaskets in for the valve covers then? I've never tore down a diesel motor in a pickup before so I'm pretty ignorant when it comes to this. I'm more used to the 50 year old tractor motors. And what should I look for, just see if they're loose or what? Thanks!

 

[DaveBen]

The pins coming out of the connectors and not making connection.

Dave

 

[dmd]

Glow plugs doesnt make that much sense. If he is towing and it smokes wouldn't that
indicate that it is already warmed up and not needing glow plugs? Smoke would be
white also I would think.