I have an F 150 1997 4.6 I have replaced the DPEF put about 200 miles on it and the check engine light came on again. Replaced EGR and drove it another 200 miles and the check engine light came back on. I took the throttle body off and cleaned the carbon. It was completely clogged. The codes is P0401 insufficent flow EGR. Does anyone have any other ideas. I checked the hoses however the upper hose on the throttle body leaves an awful lot of black residue on your hand when you touch it.

 

Possible clogged egr tube and dpfe hoses.

 

****** http-equiv="Content-Type" content="text/html; charset=utf-8">****** name="ProgId" content="Word.Document">****** name="Generator" content="Microsoft Word 10">****** name="Originator" content="Microsoft Word 10"><link rel="File-List" href="file:///C:%5CDOCUME%7E1%5CFRANKH%7E1%5CLOCALS%7E1%5CTemp%5 Cmsohtml1%5C01%5Cclip_filelist.xml"><!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><style> <!-- /* Font Definitions */ @font-face {font-family:"Palatino Linotype"; panose-1:2 4 5 2 5 5 5 3 3 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-536870009 1073741843 0 0 415 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:14.0pt; font-family:"Palatino Linotype"; mso-fareast-font-family:"Times New Roman"; mso-bidi-font-family:"Times New Roman"; color:#231F1F;} @page Section1 {size:8.5in 11.0in; margin:1.0in 1.25in 1.0in 1.25in; mso-header-margin:.5in; mso-footer-margin:.5in; mso-paper-source:0;} div.Section1 {page:Section1;} --> </style><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman";} </style> <![endif]--> I have run a wire through every pipe and hose coming off the throttle body. I did not fin a plugged line or hose. Would a bad gas cap give me a PO401 code? Thanks for any suggestions.

 

No, the quality of the gas will not cause this DTC. Were the parts that you replaced Motorcraft parts? The DPFE in particular has been redesigned and the aftermarket parts have not kept up. Good luck!

 

I was not referring to the quality of the gas. I was askingif you leave the gas cap loose and don't tighten it it will give you a code. I have read that before and I was wondering what code it gives you when the check engine light comes on in that situation. Thanks

 

use a vaccum pump and put it on the top of your egr valve and pull vaccum with the truck running the truck should stall if it doesn't you vaccum diaphram in your egr is bad... that's usually the next biggest cause. Last part would be the vaccum regulator. Good luck....