Question about 2004 Mitsubishi Endeavor

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How do I fix the codes P0401 & P0431 on the 2004 Mitsubishi Galant

The car shudders when I am in idling, like at a red light. Other than that the car runs pretty good. I had the EGR valve replaced about a month ago. Please help.

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Posted on Jan 02, 2017

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SOURCE: replacing front rotors on 2004 mitsubishi galant

Sandy, I can only assume that you have fixed whatever issue you were having by now since this post is about 4 months old but, I'd like to give an answer anyway. In order to remove the rotors you obviously have to remove the wheel first. Next you have to remove the brake caliper. To do that you usually need to slightly compress the caliper by squeezing it with a large C-clamp. After it's loose, remove the two hex head bolts, one upper and one lower, that hold the caliper in place. At this point there might be a small ring clip or two around one or two of the lug nut studs that need to be removed. A chisel, heavy wire cutters, or needle nose pliers work well to remove the ring clips. If the rotor doesn't just fall off in your hand, give it a little love tap with a hammer to loosen it and you should be all set. Please let us know how it goes. Thanks.

Posted on Feb 20, 2009

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SOURCE: Mirage Mitsubishi 2000 1.8L Rough Miss when Idle

Might want to look for vacuum leaks. Most misfires that go away with gas are caused by manifold vacuum leaks. The cat code can also be caused by the vac leak. There are different methods to find them and not real easy-but one way is to get a can of carb cleaner spray and spritz around intake areas. When the carb cleaner finds the leak--the car will run good for just and instant. Could be a rubber line or a manifold gasket. Hope it helped. Thanks

Posted on Apr 06, 2009

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SOURCE: 2001 mitsubishi galant shaking while in idle

Check your motor mounts, recently engine idled rough when in nuetral or stopped in drive, also jerked when put in reverse. took it to a automotive shop and found motor mounts cracked. Runs great now

Posted on Nov 13, 2009

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SOURCE: SEL code P0401 (2004 Mitsubishi Galant 2.4L)

Check for

vacuum leaks on intake manifold,

the air tube between the air filter.

intake manifold vacuum hose.

clean throttle plate with Berryman carburator cleaner

SEE sample picture HERE

Also remove carbon built up behind the EGR valve and the EGR passage tube.


Vacuum leak WILL offset the intended 14.7 to 1 air fuel ratio.

More un-metered air (leaks) will lean out the fuel mixture.

Use small amount of Berryman carb clearer at potential air leak area will help you identify trouble spot.

At idle,just spray and listen for the RPM surge.

The in-rush of carb clearer will increase the RPM on the motor.

Record the problem spot(s) and address it later.


EGR carbon built up require 2+ hours to clean from start to finish.

You will need a new EGR base gasket before your start.

Locate and remove the EGR valve after the vehicle is cool down.

Carefully record the connector and vacuum line (for older vehicle) location by drawing an easily to follow diagram.

Remove the EGR valve.

Inspect the location of the carbon built-up inside the valve and the EGR passage tube.

SOAK these areas with WD-40 spary.

You will need a small screwdriver,cloth hanger and lot of newspaper and time to get this cleaning done right.

RE-SOAK the carbon and let it sit for over-night will also help.

One the last round,pass a shop vacuum of the EGR valve and the passage pipe.

Install the new EGR gasket and connectors.

Allow the vehicle to warm up outdoor to burn up any remaining WD-40.

Take it for a test drive.

Please rate my answer if it's useful to you.



Posted on Dec 19, 2009

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SOURCE: mitsubishi galant 2004 key stuck in ignition

1st Remove Battery cable from Battery because the only time the air bags will deploy is when the key is in the ignition. I have tilt steering and when I put the steering wheel in the up most position. I came right out. But now it seems to stick more lately.

Posted on Jan 02, 2010

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