1997 F150,4.6, 154,000 mi, got a 401 code, EGR insufficiant flow, changed everything on EGR system, had garage check everything, checks good, stayed reset long enough to pass smog,code keeps appearing after reset.
Any solutions ?

 

If all the ports are clear and your egr is functioning then its probably your dpfe. Very common problem. Happend to me twice already. Do a search for P0401 and you'll find lots of info.

 

How well does your shop understand the EGR operation beyond replacing parts and reading codes?
That's the key to getting the problem resolved.
First, what does low flow mean.
How is the system test conducted?
What parts are most likely to be at fault?
Then testing the parts for a failure indication to narrow down the most likely cause.
The low flow test fails on too little exhaust gas flow under a controlled test condition set up by the computer. The flow is measured by the DPFE and compaired to a software table with narrow limits, for pass of fail.
There are 3 major parts and supporting connection hardware.
If there is a blockage in the intake from carbon after the EGR valve, the flow is blocked.
What has been done so far?