I have a 1997 F-150 with the 4.6L V-8. About a week ago, the check engine light came on, and the diagnostic showed the code for insufficient flow on the EGR valve. On Monday, I replaced the valve, the controller and the solenoid, and checked the harness for any leaks in the tubing. However, after about 15 minutes of driving, the check engine light came back on and I'm getting the same code for the EGR valve. Any suggestions on what I should try next? Thanks.

 

1. Can you post the trouble code?

2. You say you replaced the "EGR valve, controller and solenoid". There's no such thing as an EGR controller. Could you be describing the DPFE sensor?

3. Finally, did you inspect & clean the EGR passages in the intake manifold when you removed the EGR valve? They often clog & set low EGR flow codes.

 

I had the same problem with my truck only its a 96 f-150. I replaced the valve and everything. I don't know why it worked but i disconnected the battery cables and put them back on and the light has never came back on.

 

I have a '98 f-150, 4.6L . I have been battleing this same problem as well. I have a check engine lite with a code 401 (low flow to EGR system)I have cleaned the EGR valve, Checked the Solenoid and changed the DPFE sensor. How is your engine performance? My truck will give a noticeable shudder between 30-35 and then again at 40-45. It will not happen in fast acceleration, it only happens while trying to remain at a constant speed and gets worse after driving for a while. I have changed plugs, wires as well...no change. I also have a K&N system in but I doubt it is related. Let me know your fix

 

As per a very smart person on the F-150 forum: he claimed to remove the elbow that connects the EGR valve to the throttle body and clean the two ports that allow air to flow to the valve.
He was right on the money! The ports we're completely clogged. I removed, cleaned and reinstalled the elbow in about 1 hour. The check engine lite is off and the studder has seemed to go away. It has only been a day, but I think it solved the problem.