O2 sensor

I had the problem before and you definately have to change that o2 sensor it will run smoother after that.

There isn't really a good test to see if they are responding correctly, or quickly. You can hook a scanner up to it, but even that won't tell the whole story. They do degrade over time as the sensor gets plugged with carbon and response becomes poor.

I was reading through some past posts... Did you replace the O2 sensor? Did it help? I saw you replaced a number of things but you did not mention the EGR valve... If it is slightly stuck open the engine will not idle right. You can check the O2 output... while the engine is warm check the O2 output varies between .7 and 1.2 volts. You can find the O2 output at the diagnostic plug

Hope this helps

does anyone know if you can clean an o2 sensor? or do you just have to get a new one? im having a slight roughness starting to act up on idle as well.

scan gage

i have just hooked up a scangage which promises to read the codes from the ISO connector.

Currently there are no codes open on my T100, but extra info gages and trip info have helped me to get the RPMs and other infor off the onboard computer

I think it might tell you your O2 sensor is bad if your check engine light is coming on ...

NO WAY TO CLEAN O2 SENSOR , MY TOTA TRUCK WAS RUNNING ROUGH AND I CHANGED THE O2 SENSOR AND IT DID THE TRICK, YOU CAN EASILY CHECK THE O2 SENSOR AND SEE IF ITS BAD, REMOVE THE O2 SENSOR AND COVER THE WIRING CONNECTION WITH PLASTIC BAG AND TUCK IT AWAY SO IT WONT TOUCH ANY THING, RUN THE ENGINE SEE IF IT IS RUNNING SMOOTH IF IT DOES RUN GOOD THEN YOUR SENSOR IS BAD, FOULTY SENSOR SENDS BAD INFO TO THE COMPUTER THATS WHY THE ENGIN RUNS ROUGH, IF YOU DECIDE TO CHANGE THE SENSOR O2 I FOUND THE LEAST EXPENSIVE AT WWW,O2SENSOR.COM GOOD LUCK

My 96' 2.4 is doing the same thing. Cleaned the EGR valve yesterday, no change.
I replaced the front O2 sensor and may need to replace the rear sensor. There are two O2 sensors on the 2.4. Besure to wire brush the studs on the exhaust that hold the sensors in place and apply some lubricant for rusted bolts the day before. It will make your experience less eventfull. Use great caution not to touch end of sensor, allow it to hit anything. Sensors can become contaminated just by the oil of your skin.

[There are two O2 sensors on the 2.4.]
For some years, at least, only the California versions have the rear sensor.