2003 5.4 2V Idle issues

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Mar 20, 2023 | 01:17 AM

JA86

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2003 5.4 2V Idle issues

I keep getting the P0401 code, I have changed the EGR valve, Vaccum solenoid, DPFE sensor, and O2 sensors. Could the EGR tube possibly be the problem? The vaccum solenoid was stuck open and bogging the truck down which is why it was replaced, it seemed to work for a couple of days....the DPFE failed the tests I did on it so I replaced it as well. I replaced the EGR valve simply because it was a rusted POS. Thanks in advance for any help.
*Edit* I changed the O2 sensors because I had codes for them as well, which have been resolved.

Last edited by JA86; Mar 20, 2023 at 01:18 AM. Reason: Forgot to mention O2 sensors

Mar 20, 2023 | 12:31 PM

z31freakify

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From: Las Cruces New Mexico

Any exhaust leaks on the exhaust manifold?

Mar 20, 2023 | 11:29 PM

JA86

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Quote:

Originally Posted by z31freakify

Any exhaust leaks on the exhaust manifold?

Not that I know of, I changed the cats out on the suggestion of a Ford Tech, so I have messed with it recently. Weird thing is, the fuel trims seem to be okay...they go from -7 to + 2 on the ST but never leave that range and LT stay around +1. I drove about 45 minutes straight yesterday, and the CEL came on for the same P0401 code...I cleared it before the 45 minute drive back home and it didn't come back on. So, I assume it's just something small at this point...I think. 😂

Mar 20, 2023 | 11:31 PM

JA86

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Quote:

Originally Posted by z31freakify

Any exhaust leaks on the exhaust manifold?

I have been told that those engines don't like Autolite plugs as well, which is what I have in it. But, once it gets just passed idle it does great going down the road.