Failed Emissions test. OBD II not ready. Code for Low EGR Flow. Found EGR port clogged in intake plenum. Removed plenum and cleaned port, replaced all gaskets, check egr valve with vaccum(OK), reassembled with new gaskets, cleared codes. Borrowed Genesyis scan tool and I am able to view data stream and monitor systems, drove car, it is up to operating temp 200 degrees, EVAP system not ready, EGR system not ready and Catylyst not ready? Not sure where I should go next? Thanks Rich

The passages are plugged ! pull EGR valve an inspect passages and the pipe for a restriction or damage and repair as necessary.

Check the MAP sensor for accuracy as they can trigger a EGR code .

Have you tried Engine decarbonizing type foam to remove the excess carbon for the engine?

I would start with whatever is causing the misfire. That seems to be the core of your emissions codes. Putting all codes together it seems to be clogged injectors vacuum leak. Seems to be causing stalling too.

Depending on your Year and Model, there are some more prone to this Code than others because of the material used in the intake manifold. Ford and its affiliates switched from Aluminum to Plastic to prevent sooting.

On the old style 4.6L a passage under the Airhorn would clog and prevent EGR flow. Bad EGR flow is a Code 401. It can be a Solenoid valve failing to open, but many times it is a clogged passage as I mentioned. Sometimes a bad EGR has a ruptured diaphragm which can be checked by drawing the Vacuum out of it.

For those engines a simple $10 gasket and removal of 8 screws will allow you to scrape out the valley the passage is in.

So this fix is not real expensive, get parts at common autoparts stores.

PO401 is a egr problem, low /no flow detected. Unfortunatly most of the time with the 3.8 engine is the ports in the intake manifold get clogged. So if testing reveles the egr valve is working and the dpfe sensor is reading between around .8 to 1.2 volts at idle your probably looking at taking all the plastic plenum parts off to clean the passages. This can be done without removing the wiper box abobe the plenum but you have to remove the iac and sneek the manifold our from the drivers side forward first.

If this is a 3.4 liter V-6 the passages on the plenum clog up with carbon between the egr and the intake air passage by the throttle body. take off the valve and start the car. Is it sucking air through the passage?

Hi,

P0401 means insuffient EGR flow:

EGR stands for Exhaust Gas Recirculation, which basically sends some of the exhaust back into the engine cylinder again. Your error means that there isn't enough of the exhaust gas making it back to the intake manifold.
The first thing I'd check is the tubes coming off of the EGR valve to make sure they aren't clogged or broken. Then I'd check the EGR valve itself and the throttle body. The problem is usually:
1.) Carbon buildup causing a clogging.
2.) Broken hoses.
3.) Broken Valve.

Best regards.

I had an OBD II 401 code and fixed it by cleaning out the EGR vacuum line in the intake manifold. I removed teh EGR Valve and the set screw below it. i used a rifle cleaning brush and one length of the rod. Then I replaced teh set screw. I started teh engind and let the vacuum **** some carb cleaner through the front port hole. when it was sucking good I replaced teh EGR valve and reset the codes. That fixed it.

You need to pull your plenum and more than likely the intake and clean out the vaccum port in the intake where the egr pipe connects to the back of the intake.Not sure if you can do it with just pulling the plennum or not though.Having the same prob with my 96 rl.Keeps kicking the insufficient flow to egr valve code at about 30 miles.