1999 Ford Mustang Code P0401 and running very poor?

Tiny
JMOORE0180
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  • 1999 FORD MUSTANG
1999 Ford Mustang 6 cyl Two Wheel Drive Manual 99k miles

I keep getting the code p0401 on my mustang, EGR code. I replaced the DPEF sensor and cleaned out the EGR valve and the tube from the EGR valve (both was very dirty). I drove about 10 miles, and light comes back on, with same code. Could the EGR valve just be bad? Or maybe something elce?
Thursday, October 28th, 2010 AT 6:11 PM

9 Replies

Tiny
SATURNTECH9
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That code is for egr flow restricted you could a blocked egr port.
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Thursday, October 28th, 2010 AT 6:43 PM
Tiny
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I checked all the lines going, and coming out of the EGR valve and all seem to be clean.
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Thursday, October 28th, 2010 AT 8:42 PM
Tiny
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The best way to check the exhaust and the vacuum port is to start it without the egr valve for a few second's the engine should start to race and you should hear the exhaust leaking. If you do then you know both port's are clear.
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Thursday, October 28th, 2010 AT 8:51 PM
Tiny
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Sorry, I dont think I completely understand. Take the egr valve off? Or just take the lines off the dpef sensor?
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Thursday, October 28th, 2010 AT 9:01 PM
Tiny
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Yes remove the egr valve and start it without the egr valve for a few second's the engine
should start to race and you should hear the exhaust leaking. If you do then you know both port's are clear.
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Friday, October 29th, 2010 AT 1:14 PM
Tiny
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Ok, so I took the egr valve off, the engine seem to run the same with air coming out of the steel tube. When I put the valve back on, I put vaccum presure onto the vaccum inlet, and the engine start to die. This mean the egr valve is good, right? Could maybe the egr solenoid that the vaccum hoses connect to, has gone bad? BTW, thanks for all the help!
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Friday, October 29th, 2010 AT 7:48 PM
Tiny
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If the engine ran the same with the valve off tells me the intake port is clogged. The steel tube is the exhaust if the intake port wasn't clogged then when you removed the egr valve and started it the engine would race because you would have a big vacuum leak. Since it didn't then the intake port to the egr valve must be plugged. That would make sense since you have a egr flow code.
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Saturday, October 30th, 2010 AT 11:23 AM
Tiny
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That does make alot of sence! Is there a good way to clean the intake port out?
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Saturday, October 30th, 2010 AT 4:19 PM
Tiny
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A good way to do that would be to get some carbon cleaner put it in the port let it soak. Then get a piece of speedometer cable fray one end and figure out the length of the port make the cable a little longer then that and cut the non frayed end. Put the non frayed end in the drill and use the cable like a hone to clear the port.
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Sunday, October 31st, 2010 AT 12:51 AM

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