Below, and in my next thread, are tips on how to cure this problem.
Tools required:
-Slotted and philips screwdrivers
-10mm socket
-10mm wobblie socket (1/4 drive with 12" extension)
-22mm(7/8")crow-foot wrench to use with a 3/8 drive ratchet
-10mm gear wrench
-13mm gear wrench(if you don't have gear wrenches go buy a set of the originals!) Or, you can use regular box end wrenches if that's all you've got.)
-Mityvac hand vacuum pump (get one on ebay or from the local autoparts store like NAPA)
-Couple of cans of carb spray cleaner
-7' of 3mm cloth braided vacuum hose
-Box cutter type knife with new blade
-2' of string from a weed wacker
This job is best done on a car that's cold because you're dealing with hot exhaust stuff.
HOWEVER.......before tearing anything apart, remember this little mantra: "Always confirm the customer's complaint."
So in that vain, let's prove we have an EGR Valve with a blocked passage.....
The EGR valve is the metal flying saucer looking disk on the left rear of the intake manifold. To see it, you need to remove the upper engine plastic cover which is held in place with 4 quarter turn screws. The EGR valve is hooked to the left exhaust manifold, just at the rear of the left cylinder head (actually a bit lower, at the engine block).
To test the EGR valve, remove the top plastic engine cover, remove the cloth braided vacuum line from the top of the valve (long needle nose pliars make this easier). Connect the vacuum line to your Mityvac hand vacuum pump and pull a suction on the EGR Valve. As you do this, the engine idle should drop noticeably. If it does, you have a good EGR valve and a good passage into the intake manifold. During this test, you are also watching the vacuum gauge on the mityvac. The EGR valve's diaphram should hold a vacuum. If it doesn't, the EGR valve will need to be replaced.
If you passed that test, then you're done, quit reading. Your EGR problem lies elsewhere, so read my other thread on how to diagnose further.
Still here? Okay, let's clean the EGR system:
1)Remove the top engine cover (you've probably already done this).
2)Remove the plastic duct from the MAF (mass airflow sensor) to the plastic intake plenum.
3)Remove the plastic intake plenum. It's held on by two 10mm bolts at the top. Then, it's held onto the back of the engine by 2 pins. So to remove it, you slide it rearward. HOWEVER, the pins are located in plastic bushings that may fall out and fall down the back of the engine compartment and get lost. BE CAREFUL. Also, there is a plastic breather hose on either side of the plenum. These are super fragile. Squeeze their end "rings" rock them a little and pull them away from the valve covers first, and then from the plenum. On the left side, there is a T in the plastic breather pipe. It goes to the breather piping along the left valve cover. Undo the hose clamp there and slide the breather pipe out of the rubber hose. This left side is very tedious, so take your time and whatever you do, don't break the breather pipe....consider yourself warned!
4)Okay, with the plastic plenum and breather pipes off you can now remove the electrical connector on the left rear valve cover at the cam position sensor.
5)Now using a 10mm wrench or socket, remove the two 10mm nuts on the back of the left valve cover that hold the cruise control diaphram in place. Undo the rubber hose going to the diaphram. Unsnap the rod on the diaphram over where it has a plastic ball connection at the throttle body. Be careful with the plastic stuff here!
6)Down below this, you'll find a black metal bracket with two electrical connectors. Unplug them. Then remove the single 13mm nut that holds the bracket to the back of the engine. This is down low and hard to get to. A gear wrench is your friend here!
7)Use your 22mm(7/8") crow foot and remove the big nut on the bottom of the EGR valve, and that same nut down low on the intake manifold on the left cylinder. You'll have to turn the steering to the right fully to get room for the nut on the manifold.
8)Use your 10mm wobbly socket and 12" extention to remove the two 10mm bolts that hold the EGR valve to the intake manifold. Don't drop them!
9)The EGR valve can now be removed and snaked out of the engine compartment.
10)Okay, now you're looking a the EGR passage in the intak manifold. It will be packed full, or partially full of black goopy carbon. Place a drain pan, or a big piece of cardboard under the car to catch all this crud and keep from staining your garage or driveway.
11)Use the legnth of weedwacker string and start poking into the passage and dragging all the crud out. Once you get yourself a hole augered in it, you can use a length of 3mm braided vacuum line, the straw from your cans of carb cleaner, and your carb cleaner to start blasting the passage out.
12)Blast away and auger out the passage until your weedwacker string is coming out clean. When it's fully clean, shove some 3mm vacuum hose into it as far as it will go, then blow through it with your mouth. There should be very little resistance to blowing. I like to blast them out with compressed air.
13)snake your can of carb cleaner down the back of the engine, open the throttle plates by hand, and blast out the throttle plates on both sides and blast down into the intake in as many directions as you can.
14)Test the EGR valve. Use your mityvac to pull a vacuum on the valve and you should easily be able to blow through it. If you can't, auger it out with the weedwacker string and carb cleaner.
15)Take a screwdriver and poke into the EGR hole at the exhaust manifold to make sure it's wide open.
16)You're all done. Put it all back together with these tips....
a)Mount the EGR Valve loosely getting all fasteners started by hand before you ever put a wrench on them. If you can't start the fasteners by hand, STOP and figure out why. If you strip something out, you are screwed!
b)If the EGR gasket looks bad, replace it. If it came off okay, put some exhaust sealant on it, and reuse it.
c)Replace all cloth braided vacuum lines while you have everything apart. To remove the old lines, cut them length-wise at their fittings, then peel them off. If you do this, you won't screw yourself by snapping off any plastic fittings or lines. REMEMBER.....do only one fitting at at time so you don't get stuff out of order and create a new running problem or CEL.
This whole job takes about 1.5hrs, maybe 2 at the most. Take your time and use finesse. The results will be outstanding and you'll avoid breaking stuff and being pissed-off for a week.
If you want to dig in further, and I learned the hard way that "you" should, remove the throttle body and clean all the hardened carbon out of the EGR passage that comes up into the intake manifold. You'll see in the photo below what I dug out of mine, even after the roto-rooter service on the EGR passage that runs under the intake manifold. I was still getting the "low flow" CEL, and this was why:
