98 mazda 626 egr and o2 sensor

My bother has a 98 626 AT trans that spits, sputters, idles like crap. ran my scan tool on it and it shows 2 codes, 0400-exhaust recirculation flow malfunction and 0303- 3 rd cylinder misfire. Now on the 0400 code I guess it is referring to the EGR valve. Can someone tell me where that is located? After the mani there is a pipe coming off it that runs underneath the air box and head. Is that it. lso any suggestions on the misfire code/ Valve, rings bad etc. THanks,GAry

theres a couple of small holes behind the throttle body inside the intake that will need to be cleaned for the p0400. youll need a new gasket for the throttle body as its probably paper. as for the misfire, just change out the plugs and wires.... but use mazda parts. mazda ignition systems dont like anything but NGK brand parts

Thanks mazdatech. Do you know where I can find a shop manual for the 98 626 2.0L 4 cyl engine that will show how and where the TB is? I have the shop manulas for my 98 3000Gt Sl and for my 87 Conquest TSI. These help out more than the Haynes or Chilton. Thanks again,GAry

The throttle body is located where the air runner from the air filter box connects to the motor. Just remove the clamp and runner, and there it is. (Contains the throttle plate.) You may also want a gasket for the egr, as you will need to unbolt it from the motor to get the ports cleaned. I wouldn't bother with the misfire just yet, as egr problems can cause misfire codes. Fix that first, and your miss may go away. Use carbureator cleaner and a paper clip to clean these ports, be careful about squirting too much fluid into the engine, becuase it can hydrostatic lock it... to avoid this, I usually remove the plugs and turn it over a few times just to make sure.