O2 SENSOR on 1993 Mercury Cougar

MY COUGAR IS AKING FUNNY. IN SHORT..WHEN I START IT IN THE MORNING ,IT STARTS FINE..BUT AFTER DRIVING IT AWHILE AT HIGHWAY SPEED THE ENGINE LIGHT COMES ON AND WHEN CAR IS SHUT OFF..ITS VERY HARD TO RESTART..AND WHEN IT DOES START..IT IDELS UP AND DOWN AND BLACK SMOKE COMES OUT OF MY TAIL PIPE. WAS PUT ON A DIAGNOSTIC AND SAID ITS EGR AND EGR POSTIONING SENSOR..PUT NEW EGR AND EGR SENSOR ON..AND CAR STILL DOES THE SAME THING. THEN WENT TO AUTO ZONE AND THE CHECKED IT AND THEY SAY IT AN OXYGEN SENSOR BANK ONE..CAN THIS SENSOR BE CLEANED? OR DO I HAVE TO GET A NEW ONE?

by in Elkins, WV on October 05, 2009
2 answers 3 comments
ANSWER by , October 09, 2009
I don't think that you have found the correct problem yet. The fact that the EGR Valve and Position Sensor were setting codes does NOT mean they are at fault. It could have been that the vacuum solenoid that opens and closes the EGR valve was sticking and not allowing the valve to close or to open up too much. First and foremost, find the root cause of the valve malfunction. The Oxygen Sensor will set codes when the car is running to rich from a sticking open EGR valve. Once you find the root cause of the EGR valve problem, then you may find that the Oxygen Sensor clears itself up. (Just for the record I worked at Ford Dealerships as a Diagnostic Technician and I have worked on these very cars for these types of problems )
COMMENT by , October 09, 2009
THANKS FOR THE ANSWER..BUT IM STILL BAFELLED...LOL DO YOU HAVE ANY IDEA WHERE I SHOULD START? AS FOR LOOKING FOR THE PROBLEM..THE CAR IS GETTING HARDER AND HARDER TO START NOW...SO COULD YOU MAYBE POINT ME IN THE RIGHT DIRECTION?
COMMENT by , October 09, 2009
ALSO THE CAR ONLY HAS 55K ORIGINAL MILES.
COMMENT by , November 01, 2010
Hi Optimuskiss, Did you finally change to O2 sensor and did it fix the problem? My 2000 Cougar is doing exactly the same thing: it starts perfectly in the morning but once then is super hard to start for the rest of the day. Fuel pump maybe? If you ever mananged to figure it out, please post. Thx
ANSWER by , March 16, 2010
the o2 sensor could indeed be the problem and is one of those parts that need to be replaced periodically. The exahust collects on the o2 sensor and can prohibit it from running correctly. Also, it can just go out all together or break off. It's a rather cheap replacement for the benefits. Plus, its not real difficult to do. If your having irradic idling, stalling, louder than normal idle and acceleration, smoking and heavy fuel consumption this could very well be your problem and in many vehicles wont show on a diagnostic if it has been broken off. The o2 has a large impact on the ECM and can cause damage to the ECM over time. If you do change the o2, remember to reset the ECM by taking off the negative battery cable for a few min. NOTE> you may have to have your vehicle relearn how it idles. You can look this info. up by searching. (your vehicle)Set idle, relearn. Best of luck.