When I pull vacuum on new EGR engine stutters therefore it seems good. I have 12v at solenoid and 45 ohms across pins which I read is good, any suggestions on next thing to ck? Thanks

 

According to: OBD-II Trouble Code: P0401 Insufficient EGR Flow
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Causes:
A code P0401 most likely means one or more of the following has happened: The DPFE (differential pressure feedback EGR) sensor is faulty and needs to be replaced, There is a blockage in the EGR (tube), most likely carbon buildup,
The EGR valve is faulty The EGR valve may not be opening due to a lack of vaccuum

Possible Solutions
In fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit. Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticable difference in RPM's with the EGR open
Clean out the EGR valve and/or tubing to remove deposits Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model)
Replace the DPFE sensor (with a good quality / OEM one)
Replace the EGR valve

I can't help you with specific values!

 

Thank you, someone has already replaced the EGR and RPM's do drop with vacuum applied to the EGR so I am suspecting DPFE.

 

The PCV (100,000 mi) has never been replaced is it as easy as it looks to place, do you have any thoughts?

 

Replace it !
Mazda never does!
Make sure you line up tabs!
It turns in, not push in.

I just ordered a new one for my car, last changed in 2011! and I have low mileage! Ever clean your throttle body or MAF! Try it it might like it!

 

Thanks, I took it to get state inspected but they said I have to drive it now after I reset ck engine light.