Here's what I've learned after 11 hours of installing my damn 4g94 intake manifold. (thinking it was the problem)
So may unexpected things happen, that's why it took me 11 hours, which is usually 2...

*Make sure you read the FSM first! (17-116 - 119)

It will save you guys the hassle.

 

No I have not figured it out yet. I purchased a vacuum pump just to test it. I also read on a separate thread read that someone was having the same issue and when he replaced the ignition coils it fixed the issue. Not sure if I was to spend $100 to try but may have to.

 

I'm not even sure how it is related to the EGR system. Try to get a hold of the FSM man.

 

I just replaced my coils. I don't thing the egr not functioning properly is related. Yes as I have also just purchased a vaccuum hand pump to perform the tests outlined in the factory service manual. I also have the vaccuum solenoid and egr solenoid on the way. Going to get it solved.

 

I don't think the coils have anything to do with it either hence why I'm reluctant. I have a 2004 FSM so I'll look at that and figure it out. At this point I'm determined to put my best effort to figuring this out until I'm required to smog it in March.

I've already replaced the solenoid and I'll keep logging my attempts here.

 

I have the 2003 FSM. Have you tried using the vaccum hand pump to operate the egr valve? Or check the vaccum is maintained when applying a 12 volt source to the egr solenoid? Check the resistance on both prongs as well, it should be be 39-35 ohms. Also make sure theres the right amount of vaccuum coming from the throttle body on the green stripe vaccum line. Should be 51 kPa in one second or less. If not the egr could be restricted. All these tests r in the FSM. I'm waiting for a vaccum pump so I can perform the tests.

 

Well here is what I did today;

Traced the hoses to make sure all were secure. During this process I noticed that the entire hose system connects to two location at the Throttle Body. This is where some of the intake comes in. The end of the system is the EGR Valve where the emissions exits the system and returns to the Intake Manifold. If you take off the hoses to the Throttle Body one has a large opening while the other has a tiny (smaller than a staple) hole. I decided to remove the Throttle Body from the Intake Manifold and clean it.

While I was cleaning I noticed that the tiny hold that leads to the top was completely clogged and I couldn't even blow into it. I first blew it out with an air compressor and then shot some carb cleaner through it. Then I cleaned their entire inside of the Throttle Body. It looks like it's leaving the factory brand new.

Put it all back together according to the diagram attached.

Everything runs great. I cleared the error in the system and now I just have to drive it around for a week or two to see if it comes back (it took 8 days last time I made a change). I'll keep everyone informed.

If it comes back, fingers crossed that it won't, I will be taking the entire weekend and performing every pressure, voltage, and omh test recommended in the FSM.

 

So far so good. I have been driving it for the past 3 days and no P0401 or P0403 errors. However, I am now getting a P0171 error (System is running too Lean). I'm assuming his has to do with the Throttle Body being cleaned and the Gasket (which i didn't replace). I've ordered a new gasket ($2.99) and will try that out first.

Fingers still crossed that I don't get the P0401 or P0403 errors.

 

Lol I love this, you not alone bro I cant count how many times something was supposed to take "X" amount of time and turned out to take "XXXXXXXXXX" amount of time lol

 

YES!!! I finally fixed it!!!
Turns out, the evo tb that i bought is more ****ed up than i thought.

1.) the tps sensor is broken and i had to super glue it, which worked..
2.) the E vacuum port is blocked/clogged/deleted/****ed by the past user; therefore, it is not generating vacuum!

I'll make a how-to egr system check your car when i get some time!