gweelie

92 4runner 3vz-e 4x4 manual transmission

I have been having troubles with high idle on my runner since I've owned it, checked for vac leaks and done all sorts of tune up projects. About a week ago, my ect pwr light switched on on my dash and I found it odd since my truck is manual. I then considered a short in my dash making the light illuminate, but have since found out that it is a check engine light ( I jumped the two test terminals and got a code reading of 21... O2 sensor).

In theory, the idle issues and minor "bucking" in 2nd gear could be a result of a malfunctioning ecu, but could it in fact throw on the wrong light? I'm hesitant to replace the O2 sensor right away in the case that the ecu is bad, I'd hate to screw up the new one. Any ideas or thought? Thanks.

whokrz

Use the FSM to test the ecu. There is a link in my sig

gweelie

Sorry, where? I'm not very good at internetting. I would love to give it a try though.

4Crawler

iTrader: (3)

FSM = Factory Service Manual:

Link right above----------------^^^^^^^^^^^^^^^^^^^^^^

gweelie

ohhh, sorry about that, thanks!

gweelie

Is there any truth to my concern of replacing the o2 sensor and it failing again do to ECM issues.

whokrz

I do not know much about the 3.0. I have heard if it is running really rich it can foul an 02 sensor, but I do not know if it is true or not. When you replace your O2 sensor use a denso. You can buy them for a reasonable price at http://www.sparkplugs.com
Denso OE identical O2 sensor $66.51

whokrz

......and sorry about the abbreviation of Factory Service Manual

gweelie

i"ll order one tonight! Aside from a fouled o2 or a faulty ecm, what else could cause the engine to run rich? Im grasping at straws here

whokrz

Don't know on a 3.0 Here is a link to the trouble shooting guide in the factory service manual. http://ncttora.com/fsm/1990-1995_4Rn...e/troubles.pdf

On my 22re I have had it from air flow meter and o2 sensor. I have read that the throttle position sensor, coolant temp sensor and cold start system can also cause this but I don't know if it applies to the 3.0

I would try the o2 sensor first. If that doesn't do it go threw this with a volt/ohm meter.
http://ncttora.com/fsm/1990-1995_4Rn...e/troubles.pdf This tests the computer and makes sure the efi components are working correctly.

gweelie

I intend on testing the ecm soon, but with a VERY pregnant wife, my time is extremely limited. I'm getting the o2 sensor tonight, just hate the idea of fouling it and needing to buy another down the line. Thanks again for all of the input, everyone on yotatech is full of valuable info.