Expert: Skip Bollinger - 10/4/2007

Question
QUESTION: I just had my 1997 Mercury Sable Emission Test done today and the computer gave me some Trouble Codes that are P0430 and P0303.  P0430 is for the Catalyst System Efficiency Below Threshold (Bank2) and P0303 is for Cylinder 3 Misfire.  Is there anything that I can do to fix this without taking it to a shop?

ANSWER: Daniel,
  Just to make sure we are on the same page, if you look at my Profile, I'm a Parts Professional, NOT a tech but I will offer these thoughts for your consideration.
1.   I'm guessing, since it says "Bank 2" the engine is a V-6. You don't say what size engine it has. I would guess the Oxygen Sensor downstream of the Catalytic Converter may be causing the P0430 code. I would look into replacing it but read the last paragraph before you run out and do anything...
2.   Code P0303 for a cylinder 3 misfire could be caused by a number of things. There could be something mechanical in the engine causing the misfire. You don't say how many miles are on this 10 year old car. Also I don't know when the last tune up was. This problem could be as simple as a spark plug, wire or distributor cap. I'd begin with a basic tune up... Plugs, wires, cap and rotor if it has a distributor. Again, no engine size..? A tune up on this car, if has a V-6 could be a challenge. The rear spark plugs (the ones by the firewall) can be difficult to get to if you don't have patients and a swivel to put on your extensions. Obviously it can be done. I just don't know what you have in your tool box, your patient level or mechanical ability. I have talked to Tech that have told me, on some cars, they have to remove the "dog bone" upper engine mount, let the engine roll towards the radiator to gain access to the rear plugs. I don't know about your particular car. NOW to the last paragraph...
  Last paragraph. When a computer "sets" a code, it is telling you there is a problem with a particular system, NOT just a part. I think if I were you, I'd look at the Oxygen Sensor but also inspect the wiring. If a wire has gotten against an exhaust pipe and burned, the computer will pick that up as a bad OX Sensor so inspect your car carefully.
  Sorry, it was next to the last Paragraph. I think that is about all I can come up with now. I hope this helps but please remember I'm a Parts Professional, NOT a Tech. I thank you for your question and good luck....
Skip

---------- FOLLOW-UP ----------

QUESTION: I have some more information on my car for you.  It's a 1997 Mercury Sable with a V6 (3.0L SFI) and has 112,653 miles on it.  One of my friends told me that I might want to change the Catalytic Converter on the car along with doing a tune up to the car.  So my question for you is if I need to change the Catalytic Converter is it ok to use a Universal one to replace the Original one on the car.  I'm just trying to fix the car myself without taking it to a shop and paying labor fees for something I can do myself.  I have had the car for almost 2 yrs. now and the only thing other than changing the Oil and Oil filter that I have done to the car is last yr. I put new Spark Plugs in the car and changed the Fuel Filter.  I appreciate any help or tips that you can give me on my situation.  I know that your not a Tech, but I would like to know what you would do.

Answer
Daniel,
  Why do you want to change the Converter?? Let's do a test, Okay?? Get a piece of paper, say 5"x7". Have someone start up their car that just runs great and hold the paper to the exhaust pipe. Let the exhaust blow the paper while you hold it. NOW take the same piece of paper and do it to your Sable. Does the paper react the same way as it did in your first test? If it does, you don't need to replace the converter since it isn't clogged. Please ignore what your friend says since he/she isn't a bonified Tech and it isn't their money!! An OEM converter for your car costs about $575.00 to $600.00 depending on the engine code. A "universal" converter is $100.00 plus all the adaptors you will need to make it fit. If you can weld, you may get off a bit cheaper.
  Why don't we start at the beginning. You gave me codes that have been set. What have you done since then? What symptoms does the car experience? What is the 8th diget of the VIN?? This can be viewed through the driver's side of the windshield looking at the dashboard. I'm thinking it should be a U or 2.
  Anyway, keep in touch and don't listen to "neighbors". Like I said, they aren't pros and it isn't their money..
Skip