95 caddlilac seville STS getting horrible fuel economy.

Your vehicle has 2 catalytic convertors. The replacement used should be one made expressly for your vehicle. Cahoots told you that a convertor is defective? You may only need an O2 sensor.

Kia take more than one O2 sensor, and they are probably original equipment, so start there. Also, replace plug wires. There is also a fuel filter that is the old style filter, needs replaced too. This sounds like all it needs to me is some TLC!!! O2 sensors are going to be $130.00 or less. Plug wires are $30.00. Filter-$10.00. Not too bad a price to get your performance and economy back!!

That should not cause it to be sluggish, but- It will hurt fuel economy..... The O2 Sensor(s) play a limited role in fuel control....

Your engine has 3 O2 sensors: one in the collector section of each exhaust manifold and one just after the catalytic convertor (the one up above the riveted heat shield). So you have two sensors upstream of the cat and one downstream.

Keep in mind that many vehicles have two O2 sensors, one upstream of the converter and another downstream of it. I could see that a compromised old one downstream could report (via voltage generation, that's what they do and how they work) that the converter isn't doing it's job. If your vehicle has more than say 90,000 miles on it, they should be replaced unless you're not worried about excessive emissions, lowered fuel economy, or a converter being damaged gradually by improper fuel/air mixture due to a worn out O2 sensor.

The code found P2097 is 1/2 O2 sensor rich (downstream- below the catalytic converter). Your previous code is related to the same O2 sensor.

I would recommend replacing the O2 sensor then go from there. If it returns then you will have to start testing the wiring. I would recommend changing the O2 sensor now if you are able to.

It is simple to replace and easy to get to. The trip would be a good chance after the repair to see if it returns with the number of miles you would be driving.





1. Oxigen Sensoir connector
2. Catalytic Converter
3- Downstream Oxygen Sensor
4. Engine Harness connector.

It can have an effect on engine performance and fuel economy. So the sooner you replace it the better. I dont believe it will leave you stranded on the road anyway by any means so I wouldnt worry about that if you arent able to replace it right away before the trip. If you need more help or have more questions then let me know and I will help you further.

Hope heplp with this (remember rated this post).

Yes, Have the dealer check and verify before buying one. Make sure all is good, that nothing is "killing" your converter.

Usually horrible fuel economy comes from bad oxygen sensors, especially if the engine runs well. Oxygen sensors tell the engine how much fuel to add to the air it's taking in based on how much oxygen is making it out the exhaust. When they go bad, typically the computer's telling the injectors to dump tons of fuel into the engine, because it thinks there's too much oxygen making it through, meaning a lean mixture. They're normally good for about 100,000 miles on modern GM vehicles. and are easy to replace. You have 2 of them that matter for this purpose; one on each y-pipe, between the exhaust manifold and the junction of the "Y" before the catalytic converter. You will need to replace both. They look like a spark plug with a bundle of 4 wires to lead to the engine compartment. If you lay down and slide under the truck right behind the front wheels and look up, you should be staring right at the sensor. The best method of replacing is with a special socket that you can get at any parts store that allows the wires to exit the side of the socket. You do have a total of 4 of these sensors; 2 in front of the catalytic converter in the y-pipes, and 2 after the cat. The two after have no effect on the mixture; they are only for the emissions controls. Finally, 90% of the time, O2 sensors are responsible for poor fuel economy and poor emissions.

If you haven't replaced the O2 sensor that is causing your check engine light to come on by generating a fault code in the ECM, replace it first. Cleaning the Catalytic Converter is not the thing to do. Replacing the faulty sensor will pay for itself in the long run with the better fuel economy you will get.

if you have the northstar you have 4  O2 sensors.  one in each exhaust header.  one before the cat converter & one after the converter