How to lower your NOx readings hopefully on your F22B1 by cleaning the Exhaust Gas Recirculation System
Tools Needed: Socket wrench, 10mm socket, 10mm, 17mm, 12mm wrenches and sockets, flat head screwdriver, small amount of motor oil, rag or towel, something to clean the ports, new fuel injector washers are recommended .
1) Disconnect the negative terminal on your battery with a 10mm wrench, and loosen your gas cap to relieve pressure.
2) Using a 17mm and 12mm wrench, relieve gas pressure to the fuel lines by loosening this "banjo" bolt one turn with your towel on top in case of any severe leaking.
3) Remove this connector from the FIA solenoid, also unbolt the solenoid for easier movement of the fuel line later on.
4) Remove the two lines marked in yellow, the orange one remove after step 6.
5) Remove the 4 plugs from on top of the injectors by prying the clip at the yellow arrow to the direction of the orange arrow, after the metal clip on one side is loose, pry at the other side of the metal clip and pull up.
6) Unclip the plastic wiring cover from the two spots on top of the fuel rail, and place it out of the way.
7) Remove the three 10mm nuts from the fuel rail.
8) Remove the fuel injectors from the intake manifold along with the fuel rail. Now you can see the EGR port cover. Remove the five 10mm bolts.
9) Remove the cover by sliding it toward the windshield, you will see the blackened lower section of the EGR section. Clean the lower cover holes caked with carbon buildup.
10) Slide the lower cover over with the top piece. Now you will see 4 small and one large EGR port. Clean these with a brush or wire. On my 92k mile car I had 2 ports clogged shut.
11) Put some oil on the injector washers to prevent leaking, and replace the fuel rail with the injectors. It is recommended to replace the washers, but I didn't and had no problems. Line them up perfectly and turn them a little to get them back into the intake manfold. Replace everything in reverse order, all vacuum lines, nuts and bolts.
12) Turn the key in the ignition to ACCII 3 times to build fuel pressure, check for any leaks. Start the car, it may start a little rough because the ECU has to recalibrate. Once again check for any leaks and you're done.