Mazda Repair: rough idle on 1993 Mazda Protege, spark plug wires, vacuum leaks

Question
1993 Mazda Protege has a rough idle, but runs fine otherwise. Does this car hava an EGR Valve? Gave it a tune up (spark plug wires, distributor cap, rotor, spark plug ,air and fuel filter. Still rough idle. Check fuel pressure. It is good. Notices there is a valve on the side of the intake manifold that has vacuum going to it at all times and was not familiar with that system. It has a electronic valve that controls vacuum to it, but once again I am not familiar with it. Didn't think it was an EGR valve. No noticeable vacuum leaks. I am stumped. Changed the oxygen sensor. Checked the compression. Car runs great , just Idles real rough. Any suggestions.

Answer
Hi Adrian thanks for asking..
that vacuum line that you see is for the intake manifold shutter valve, it is an emmisions relateed component. Im not to sure but if I can recall this engine does not have an EGR valve. I would check the engine for vacuum leaks by spraying it down with a throttle body cleaner or intake cleaner. if it stalls out or runs even worse, then concentrate that leak to be where you have just sprayed the cleaner.  It is poosible that there is an EGR vavle on this engine, and the way to tell if there is one on these vehicles is to just look at the exhaust manifold, if it has a steel tube going from the manifold to the intake then the ERG is usualy locted clost to the tube on the intake manifold.
Get back to me if you have any more trouble
Good luck
Chris P