Check engine light.

[laureena23]

My check engine light came on Monday morning. I have an 02 sensor that I know I need replaced but it has started doing some strange things...

The other day I was at the store and went to start the 4Runner and it didn't start right away. I had to try two more times to get it started. Then today I was stopped at a red light and the whole vehicle just started shaking very badly to the point where I thought it was just going to shut down. I turned the radio down to see if there were any noises, just a loud noise from up front.

Any ideas on what this could be? Would it be the sensor causing this? I'm kind of apprehensive about driving it, I'm afraid I'm going to get stuck on the road.

Thanks!

 

[004Gunner]

Your sensor could cause the problem. Get it replaced before you start diagnosing anything else.

 

[Ron Helmuth]

any update?

did you get your O2 sensor replaced? Any update young lady?

 

[GoHideTheAsian]

if you have a bad o2 sensor and the ce light it p0420, it may have caused you to go into limp mode. exactly how it sounds.

 

[jsmarine]

Could be a miss-fire too in addition to the O2 sensor, just a thought from your description of the shaking, could be a bad spark plug, or bad wires.

 

[Nuke]

A bad O2 sensor wouldn't normally cause idle issues. Go to Autozone or any other parts store that offers to pull the code for free. No sense guessing. It could be a # of things. Can you provide any more info? When it was shaking, what was the idle speed? Fluctuations? When you went to accelerate, did it pull away smoothly or was it erratic? How many miles on the car? How many miles since the last fuel filter change? Spark plug change?

 

[jsmarine]

Good point Nuke, no sense guessing yet, pull the code and start with that.

 

[laureena23]

Yea I took it to Auto Zone when the light came on and the reader said it was a sensor. Also not sure if it is the front sensor or the rear sensor?

It hasn't acted up since I made this thread but when it acted like that, I was slowing down to stop at a stop light. When the light turned green, I went slowly because I wanted to make it into the parking lot since I didn't know what was going on. The shaking/vibrating slowly went away as I accelerated.

I replaced all plugs about 2 years ago, last filter changes were done about 2 months ago. The 4Runner has roughly 107,500 miles.

 

[TheDurk]

Yea I took it to Auto Zone when the light came on and the reader said it was a sensor. Also not sure if it is the front sensor or the rear sensor?

It hasn't acted up since I made this thread but when it acted like that, I was slowing down to stop at a stop light. When the light turned green, I went slowly because I wanted to make it into the parking lot since I didn't know what was going on. The shaking/vibrating slowly went away as I accelerated.

I replaced all plugs about 2 years ago, last filter changes were done about 2 months ago. The 4Runner has roughly 107,500 miles.

You really need to get the number--usually that will tell you front or rear. P0420 or P0141 is rear, and as far as I know, rear sensor will not put you in 'limp' mode or affect drivability in any way. It just sets codes. [The exception would be a totally plugged up cat, but you would have the p0420 for a long time for that, I would think.]

Front sensor has several codes, p0125 is one, and does affect drivability and can keep you in open loop--which is where the ECU ignores the sensor and decides on timing, mix without feedback. Open loop is normal on start up, but system then goes to closed if all is normal.

Any o2 sensor code will specify Bank 1 Sensor 1 (which is front) or Bank 1 Sensor 2 (which is rear). There is no Bank 2 without dual exhaust. There are other sensors besides the o2 sensors that could cause your problem, the code would help us rule those out. Are you sure they said oxygen sensor and not just sensor?