The check engine light on my '96 Sidekick came on a while back and the code checked out to be an EGR code.  I changed the EGR valve (140 bucks, yikes!) and this shut the light off and helped me with the problem of it idling way too low at a stop.  After a week or so, the light is now back on, reading the code for EGR flow problems again.  My 'Kick runs just great though, no problems and great gas mileage still.  Any ideas what could be my problem this time?  Any ideas would be greatly appreciated, thanks!

How would the ECU know if the EGR is not working? Do you have the vacuum operated valve or the electrical (stepper motor) type.  Presumably the ECU is monitoring the current into either the solenoid valve or the stepper so the problem will be whichever component you have fitted. The engine will run OK if the EGR is stuck shut so thats likely to be the problem. Check the electrical connectors and the vacuum lines

Now my 'Kick is doing the super slow idle at stop signs and stalling at idle sometimes.  I am going to check for any vacuum leaks and see if I have any sort of bad wiring connections.  If none of these things are the problem, does anyone have any ideas what could be wrong?  Could it be the part right above the EGR valve that the book cals the vacuum modulator?  From there a hose goes to an electircal plug of some sort, anyone know what this is?

I have a 98 Tracker 4WD Auto that has the EGR problem.  Are you getting the P0400 code?  I failed emmissions last August and after resetting the ECU many times I finally passed a few weeks ago.  It was a good thing because out here in Connecticut if you don't pass emmisions, you will not be able to renew your registration and my registration expires on 5/26.

Anyway, the light came back on just a few days after passing emmissions.  My next step to fix this problem for good is to remove the intake manifold and clean out any carbon build up where the EGR valve attaches to the manifold.  I tried doing that by taking the EGR valve off, but there is just no room to work with up against the firewall and impossible to see if there is any blockage.

Anybody have any advice on removing the intake manifold?  The online manual from Autozone says not to use a pry bar to seperate the manifold from the engine.  Should I use a block of wood and a hammer to persuade it?

Now my 'Kick is doing the super slow idle at stop signs and stalling at idle sometimes.  I am going to check for any vacuum leaks and see if I have any sort of bad wiring connections.  If none of these things are the problem, does anyone have any ideas what could be wrong?  Could it be the part right above the EGR valve that the book cals the vacuum modulator?  From there a hose goes to an electircal plug of some sort, anyone know what this is?

The vacuum modulator is the bit that opens and closes the EGR valve. The hose goes to a Vacuum Solenoid Valve (VSV) that switches the manifold vacuum through to the modulator. If you unhook the plug to the VSV and put 12V on the pins it should open. You should also see 12V on one of the connector pins, it will be present whenever the ignition is on. The ECU switches the ground side to activate the solenoid.
Code P0400 is on OBDII code, I'm not sure if the 96 is OBDII.

Yeah, that is the code I am getting when I hook up the code reader.  I will try testing the modulator the way you described and see what it does.  Hopefully I won't have to take the manifold off and clean it like the one guy said.   

The check engine light on my '96 Sidekick came on a while back and the code checked out to be an EGR code.  I changed the EGR valve (140 bucks, yikes!) and this shut the light off and helped me with the problem of it idling way too low at a stop. 

I have a Spanish '9 8v Kick/Vitara, and the Check Engine light always comes on for the last 5 years , usually after I drive it for 5-10 minutes. I also have the very-very-low idle problem, so when I went to the shop they told me that the problem code they see refers to a malfunctioning speed sensor inside the speedometer, which instructs the ECU to adjust idle rpms when you're rolling on downhills at idle (or something like that). I didn't fix it, as the complete instrument panel was way too expensive for me...
After so many years, it seems that I adapted my driving style to the problem, so I don't even notice it anymore :-) I just check that the light is off when I start the engine, just to make sure that the cause is not a new one :-)

For the P0400 code..

Seen this link?

http://bbs.zuwharrie.com/content/topic,27769.0.html

I have a Spanish '9 8v Kick/Vitara, and the Check Engine light always comes on for the last 5 years ,

Your profile says 99 Vit. If you've had this problem for 5 yrs wasn't it covered by the 3yr warranty?