02 prizm with 2 codes po420 and po135 i already changed both 02 sensors and the cat engine light is still on and its getting expensive i need help figuring this out?

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the po420 could also be a misfire or vacuum leak
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If you changed plugs wires forward 02 sensor and throttle sensor but your 200 Ford Escort is still running idleing rough what do you do next?

you might want to check your egr valve. if it's stuck open and leaky just a little bit it will almost kill the engine. it's easy to check if you have a vacuum pump. they are cheap and available at any auto parts store. the procedure is in the chiltons manual. if you need more detail just yell. I'm h (MORE)

What should you do if the shop says your 2000 Metro with 155k miles needs a new cat converter and 02 sensor but that's expensive and it runs fine?

My sense is that these components last somewhat longer than firstanticipated, probably because of the leaner mixtures we're using,and the no-lead gas. It can be expensive. But you probably couldchange out the oxygen sensor yourself. It's usually accessible, andit ain't brain surgery. The converter i (MORE)

Can you change your own 02 sensor?

Answer . I changed my downstream sensor by driving the car, 2000 Alero, onto ramps then I set the emergency break. I disconnected the battery to reset the computer before I removed the sensor. The sensor on this car was located on a short pipe between the converter and the muffler. I guess tha (MORE)

You have a 1996 Ford Windstar which sensor would you need to change if your error for the check engine light reads bank 2 sensor 2?

Answer . The sensor in question is the downstream catalyst monitor (O2 sensor) located on the exhaust pipe that comes off of the front exhaust manifold.. But we really need to establish something so that you do not replace parts unnecessarily. A fault code from a sensor, especially an O2 sensor (MORE)

If there is a code for map sensor and 02 sensor does this mean the cat converter is bad or plugging up?

'88 o2 sensor not grounded. if the sundance is an 88 it will have a three prong lead. Plymouth realized that it was not getting enough ground (mopar EEK forum) I've wrapped a wire aroung mine and ran it directly to the negative terminal. code 52 is gone. As to the map senor. try this forum http://m (MORE)

You have a 2001 Nissan Pathfinder se and the check engine light is on you have been told it is bank 2 sensor 2 downstream 02 oxygen sensor which sensor is this and how difficult to do?

Answer . I have the same car & just changed it myself. It's the driver's side, when standing in front of the car, you should see a red cable that connects on the right side of the engine & runs behind & down then twists into the exhaust pipe next to the cat. The bad part after getting the sensor (MORE)

Why would emission code P0420 still be coming on in a 2002 Chevy Impala if you already changed the catalyst converter both O2 sensors and the coolant sensor?

Answer . \nYou have the code P0402 which is Catalyst System Efficiency Below Threshold (Bank 1). You are throwing parts at the problem without actually knowing what is wrong. This could be nothing more than a simple vacuum leak, a malfunctioning EGR valve, or carbon buildup in the EGR system, and (MORE)

2001 Pathfinder engine light problem you replaced 2 oxygen sensors then replaced 2 timing sensors the service engine light still on computer shows no code?

Wrong scanner?? If a check engine light is on, there are codes. Timing sensor? Check engine usually means a problem... Service means that scheduled service needs to be performed like oil change, or timing belt replacement. I would Check your Catalytic Converter. What often happens is the catalys (MORE)

My 2000 ls has the check engine light on. It reads lean and i replaced both front 02 sensors but light still comes on. The car runs fine but turns off at idle regardless if in drive or park. HELP?

Answer . \nSince you didn't mention the make or model of the vehicle, you will have to look at the following... A lean O2 sensor does not usually mean that the O2 sensor is bad. Since your idle is bad, you need to look at other air/fuel controls such as EGR, MAF, MAP, IA, injector nozzle and a (MORE)

Why is the check engine light blinking in your 1999 Mercury Courgar Already change 2 sensors?

Answer . \nMaybe the sensors you changed out were not the problem. Post what the symptoms were, what the codes were, and why you changed out what sensors you did. Sometimes errantly the wrong part is diagnosed as being defective, like having low fuel pressure and people spend $500 for fuel inj (MORE)

What would cause a 96 t100 to run very rough i have already change plugs wires 02 sensors and it doesn't appear to have air intake leak computer says 2 cyl. misfire any ideas?

Check under the hood at night or in a dark garage for spark arc. Mine would arc or ark from the spark plug wire to the coil on the passenger side of the motor. Spray with WD 40 or silicone to stop the ark then replace the coil and or wires. About $60 for the coil and 50 for wire set. You only get th (MORE)

1999 jeep sahara change both oxygen sensors engine light still coming on with rear flank on the computer?

Answer . \nI dont know what codes you were getting. double check the connections. And get the code cleared. retry it. If it still comes on reread the code to see what it says. You didnt get anything on tips of the o2 sensor did you? \nAnother thing the rear one refers to the one after the Cat co (MORE)

Why doesn't the check engine light go out after you replced the 02 sensor and reset the light?

Check engine . \nFirst you must know that replacing the O2 sensor is what is needed to repair the problem indicated by the check engine light. Then you need to be sure that you replaced the right sensor( most vehicles have more than one). If all this has been done give the computer a chance to re (MORE)

What does an 02 sensor do?

Answer . \nThe oxygen sensor reports live information about the engine's air/fuel mixture to the powertrain control module,(Computer). This information is used primarily to help calculate fuel delivery to the engine, which changes continuously while it is running. If the engine is running lean, (MORE)

What are 02 sensors?

O2 sensors are located on the exhaust system in todays vehicles, they monitor the oxygen levels in the engines exhaust gases. They send that information to the vehicles computer which inturn regulates the engine's fuel system for a clean burn.

Where is the 02 sensor?

It depends on the year, make, model, and engine. They are always in the exhaust stream near the engine.

What is a 02 sensor?

oxygen sensor ( in the exhaust , the sensors closest to the engine are used to " sense " the amount of oxygen in the exhaust to send a signal to the PCM so the air / fuel mixture for the engine is adjusted under various conditions )

Check engine light will not go off changed both 02 sensors still stays on?

The sole function of the 'check engine' light is not totally restricted to malfunctioning oxygen sensors. There are a myriad of things that can cause this warning indicator to illuminate on the dashboard. When it come on, there is a code number then stored in the computer's memory - requires a speci (MORE)

How do you reset the computer after changing the 02 sensor on a 1998 Chevy Prizm?

Unplug the battery of the car and let the power that is in the system drain. You can do this by wither letting the car sit overnight or hitting the breaks once the battery is unpluged. Another method is to remove the main fuse and let the car drain its power. http://www.clublexus.com/forums/per (MORE)

How expensive is 02 sensor for 2000 mercury sable?

my mercury 2000 sable is running lean--how expensive to fix? . Replacing the O2 sensor? . The way I read this, is the questioner want to purchase a new 02 sensor because the vehicle is running lean(??) The sensor is not the CAUSE of the lean condition - it is only the sensor which reported (MORE)

How do you change the 02 sensors on a 98 Malibu?

you have to get a o2 sensor socket at any auto parts place, the best way to change is run car for a few minutes, then shut off, jack up car .the sensors screw out! be carefull that you do not harm the sensor wire. or you can make a socket from a deep well socket. just cut about a half inch slot one (MORE)

You get a too lean or rich fuel code on 1998 Windstar and recommendation to change the heated 02 sensor bank 2 sensor 1 so how do I change it and where is it located?

Why blame the sensor? The sensor is reporting the data - so people tell you to replace the sensor instead of finding out WHY the data is triggering the codes? Do people buy new thermometers every time one reports they have a fever? There are codes that very specifically address a sensor failure. (MORE)

What does it mean when your engine light is on in your 02 Dakota?

The check engine light (service engine soon) comes on and stays on when a problem is detected by the self diagnosis system of your vehicle. Generally, the problem is in the emissions or something that is affecting the effectiveness of the emissions, but other causes can trigger the light to come on, (MORE)