Mazda Repair: Protege running lean, lean mixture, o2 sensor

Question
I have a 99 and 98 protege 1.8 with service engine light on. Had it checked out Sept 05 with an indication of mixture lean,but car was running fine,,now my 99 is a little ruff especially at idle/low rpm. At one time I heard in some forum that the problem could be with the Egr valve ???
Any thoughts ??


Answer
Hi Slw thanks for asking.
 When an engine light comes on for a rich or lean mixture running condition, alot of the times it is usualy a bad O2 senson, and on these proteges they where bad for blowing the three way catalitic converter. which can give you an O2 sensor failure. AS far as the Egr probelm. These 1.8's and 1.6's. Were never blowing EGR valves they had a common problem with building up carbon in the vacumm hose and the passage way to the vacuum hose throught the throttle body, So the EGR was inoperative. All it takes is to clean that passge way out and it should be OK. But there have been a couple of instances where i hade to change the EGR, But it is very rare.
Good Luck
Chris P