Ford Mustang V6 4.0P0401

Code says EGR valve. I replaced that and the same code is coming up and my car isn't running very well. Any suggestions as to what it might be? The code is P0401


Hello. Could you please post the exact code number so we cah help you? If you forgot the code number, many parts houses will read the code for free. Please write the code number down and post it here. Thanks

Being way2old is why I need help from younger minds I'm gonna guess P0401 & changing the EGR valve didn't fix it...
I'm gonna guess, too. DPFE? and/or plugged passageway? Another guess: AutoZone?
Loren
SW Washington Not to sound cruel, but we really need the year of the vehicle before we jump to confusions. lol
I do like the DPFE sensor. If I had a nickel for each one I sold, I'd be able to moderate here full time. lol

Steve
Good point. I don't recall seeing a 4.0 in a Mustang.
Loren
SW Washington They did have a 4.0 starting in 2005
 

I'll be darned. We don't see too many of the 'newer' stuff. About the only ones that new are state motor pool rigs that we do.
Loren
SW Washington That's right... it says insufficient flow. How do I fix this?
Sara; We need to know the trouble code. Insufficient flow could mean a plugged passageway between the throttle body and EGR or a faulty DPFE sensor, or the high temp silicone hose that connects to it. Even knowing the code, may take some diagnostics to determine which is causing the code.
Loren
SW Washington

P0401
This code can be caused by insufficient vacuum to sensor, faulty sensor, faulty or plugged EGR valve, or faulty porting. If you can give us the YEAR of the vehicle we may be able to get more info for you.

Steve
it's a 2002
The 4.0 wasn't listed as available in the Mustang in 2002

There is a few checks you need to run. 1st as everyone is saying is to make sure the EGR port isn't plugged. This is easy enough to check, while the engine is running just put a vacuum pump on the EGR valve, pump it up & engine should start to idle rough or die, (if you don't have a pump you can use a manifold vacuum line off the engine in place of that). If it does this indicates the port is clear & the valve is working. On Fords a common problem as Steve mentioned is the DPFE valve (differential pressure feedback egr) This valve basically sees if there is egr flow, when is goes out even though there is flow the valve doesn't see it & codes. There is a flow chart for this and maybe someone can post the chart. Even though the odds are high, I wouldn't blindly put one on without checking it out 1st.

Just so you know, I wasn't making light of your problem. My earlier post was just frustration at people at parts stores & who drive tow trucks who pass themselves off as diag techs where people take them at their word and waste alot of unnecessary money.
I found out it is not clogged and there is no vacuum leak....I was told it might be the DPFE valve by a tech friend of mine, so I guess that's my next trial now that 2 people said the same thing. I did not teake offense to your comment. I appreciate the help. Thank you
 

I am not the first owner of the car, so I have no idea what altercations were made to it. I do know that it is a 4.o