Hi,

My truck has a small miss at 1200rpm with no check engine light coming on. When it is cold it is really noticable, as it warms up to normal it gets better, but always runs a little rough at 1200-1500.

Any help with this would be greatly appreciated, getting 12 miles to gallon at best loaded or unloaded.
Have hypertech tuner, afraid to install it.

Thanks,
Scott
02 f350
147k
6 speed

 

Check the wiring harnesses going into the valve covers first for burnt or melted pins. Could also be the UVC harnesses inside the valve covers. I see both melt sometimes. Pretty easy fix, just have to narrow it down to shich one is bad.

 

Why do these harnesses melt?
Is it heat?
Chafing and shorting?
Common to newer and older PSD's?

 

Thanks for the info. BTW what does the wiring or harness go to? sensors?


Scott

 

The wiring goes to the injectors and glow plugs. Not sure exactly why they melt but I see it in all years. It can cause misfires, glow plug problems, etc.

 

My fuel guage is stuck on empty, is the sending unit wired with the fuel pump?
Can I replace only the sending unit for the guage?

 

I believe you can replace just the sender on an 02. Not 100% positive as I dont see them fail that often.