F-350 headaches
 

Problems with a 99-F350 7.3 4X4 Superduty. Has 110,000 miles, never had a problem until recent. Would shut off while driving. Changed Lift pump, still having problem. Took into Ford for CPS, shut off stoped, but a miss started. At idle you can hear the miss, shakes real bad, until you put it in overdrive. At 40 mph, shakes, but stops after 45mph. Runs okay after that, but still has a miss. No codes pops up. One time it came up misfire, but never was able to get that or any other codes after. HELP!
Any Idea where to look?

wrong fourm u need the power stroke fourm this is the idi fourm

Welcome F-350 headaches to FTE, There is a lot of good help on this site, you should get some other people chiming in. As for your problem there is a wiring harness that connects at the top edge of your valve covers that fire the injectors, the harness can chaff and the connectors can come loose under the Cover. Here is a link to some pics and testing procedure. https://www.ford-trucks.com/forums/8...jector+harness

Sorry for the long address, I don't know how to do it the short way, just open a new window, copy and past in the new window. or just click the address.

Sorry to ask you to get real specific on this, but when you go from 40 to 45, is your trans shifting gears?? Then it runs better, like when you go into overdrive?

I agree with "Want-to-Be".. probably under the valve cover plastic plug/s has come loose.. Mine did the same thing at 60K... If so, you can fix it for $0.. just following the link he provided.. Did your SEL light come on? You should also get your fault codes read for a better idea what is going on... Welcome to Forum...

I would also check the UVCH, also when was the last time you changed your oil and fuel filter?

Could have gotten a faulty CPS, or have a bad wire at the plug going to the CPS. Since the problem changed when the CPS was replaced, that's where I'd be looking real hard. Some CPS's are bad right out of the box.

They need to look into that, I haven't had one fail but i did notice a light miss with the newer one when they "updated" it.