Fun new problem Finally get my engine up and running and it lasts all of one week. Now, I have a miss (sometimes violent) at cruise. It happens at pretty much any RPM, as long as I'm off or only barely on the gas. Hitting a hill and adding load to the engine makes it go away. Hitting the gas a bit makes it go away. Someone suggested that I disconnect the vac line to my EGR valve to see if that helped. I did so and immediately the truck was running smoothly. So, I figure the EGR is bad. Well, I replaced the EGR valve, no luck. I also replaced the vac control valve (F63Z-9J459-AA) and the EGR differential pressure sensor (F77z-9J460-AB).

None of that helped. Still when the vac line to the EGR is connected, it runs like crap. Disconnect the vac line and all is well. What the he11 is going on here?

 

Could be the DPFE sensor, could be the silicone lines from the EGR tube to the DPFE, or could be your chip. Are you still running my chip with the new motor? I can shut the EGR off if you want, but it's good to have. If you replaced the valve and the solenoid, then something is causing the PCM to command too much EGR at cruise.

 

I think the DPFE sensor is one of the things I replaced. The ford part description is SENSOR ASY-EGR (see PN above) but it's the one with the two lines coming out of the hard egr pipe into a square box with an electrical plug. I guess maybe one of the lines could be plugged up; would that cause the sensor to mis-read and hold the EGR open?

What's the advantage to keeping the EGR active? Also, I dont think it's the chip itself because it does it both with the autologic and my diablo which have different tunes.

 

Just plug one end of the line and attach the other to vacuum tester to see if a line is the problem.
I still think you may a vacuum line switched with another.

 

I have a problem with my EGR or something connected to it. I has a SES light come on, so I went to AutoZone and they scanned it and the code P0402 showed up with the description EGR Flow Excessive. Does anyone have any ideas as what to do about this????

Thanks
Damon

 

The EGR valve may be carboned-up, holding it cracked open. You could remove(when cold) it and scrub it with a wire brush. Don't use any solvents/degreasers as they will damage the diaphragm.

Dan

 

!

 

I have the same issue, how much did it cost you to replace those parts?

 

I just got rid of my whole EGR mess. Blocked everything off and turned the EGR off in my chip. Running great!!