Hey Guys,

I have been reading hear for sometime. I have found lots of info here and at 4x4's Wire Trail Talk. But I am needing help with a problem with my 4Runner.

I had a serious loss of power about month ago or so! There was no loud bangs or anything of that nature! Just driving down the road and whooooooosh, loss of power! It starting idling rough, so I thought the timing slipped! I bought the Runner used and the people I bought the Runner from said the Timing Belt was replaced at 60k. Well, if that is true, than there is 100k on the belt! Took it into the stealers, no time to do it my self!

Before the stealer, I got a check engine light. Jumpered the diagnostic pins and got a trouble code 25. That lead me to believe the timing as well. I check all the spark plugs, they look good! I have not done a compression check yet!

According to the books, chilton's and hayne's, the problem could be fuel injectors, O2 sensor, knock sensor and ignition signal!

Please help, this is my only ride for now! I cannot afford the stealer! Any and all help will be appreciated!

Thanks

 

I also got a trouble code 25 in my 4 Runner. I know that my truck is a couple years older than yours. The code for my car meant that it had run lean for more than 90 sec. I have a buddy that works at Toyota and he told me that it was either the O2 sensor or the engine coolant temp sensor. I replaced the O2 sensor and it ran me about $125 without tax. After replacing this my car ran much better. I was told by my friend at Toyota that the coolant temp sensor does not go out very often. It's only like $60 but the sensor is located on the back of the motor and I believe is hard to change. The O2 sensor is easy to change and I would recommend doing this first. You also need to do that timing belt asap if you haven't already. Bad things happen if it breaks.
I hope this was some help.

 

A vacuum line coming off can cause a similar problem.

BTW, several members of this forum, the one's that could probably help you the most, are Toyota service techs. I'd suggest that you stop referring to them as stealers if you ever want help from them.

 

Loss of power all of a sudden and rough idle seems to indicate a vacuum leak somewhere. Check all the hoses since it's the cheapest and easiest thing to do.

If you have a suscipion that your timing is off, get a timing gun (around $25 - $35 at your local auto parts store) and check the timing off. You can verify for sure if it's timing related or not.

The knock sensor would retard the timing if a knock was detected. Again, check the timing at idle and verify if timing is off.


The O2 sensor going bad shouldn't cause a rough idle condition, but it may contribute to poor performance since the ECU should richen the fuel conditions due to a bad O2 sensor or go into a "limp" mode. $125 for an O2 sensor is extremely high!
Is it a wideband O2 sensor (I believe the wideband NTK11 O2 sensors sell as cheap as $150)???? Narrowband sensors for a typical automotive application shouldn't cost more than $40.

Checking fuel injectors can be laborsome since you'll need to pull them out and have them flow tested. You could do a simple functional test if you can find the injector wiring harness and stab in some tester leads (basically an LED that plugs directly to the injector signal and +12V line).


What do you mean by "whoooosh" in your description?
Did the truck actually make that noise???

J

 

That was an O2 sensor straight from the dealer. It was the OEM part for my vehicle.

 

Hey Guys,

Thanks for all the wonderful help. AJatx, the whooooosh was not a sound but me just trying to give a visual about the lost of power. Driving up a hill in 4th gear on the highway at about 50 or so and the motor went from 50 or so to about 35 - 40 or so! That is the whoooooosh.

I have 155K+ miles on the motor! So I have replaced the O2 Sensor, Cap and Rotor, and I am still coming up short, no power! I am going to see about the fuel pressure regulator and see what if anything that will do!

Thanks again for all the help. Greatly appreciated!

Markus AKA Wild Bill

 

Is this a 95 runner with a 3.0L or 3.4L . I belive its late 95 they switched to 3.4L v-6.

My advise in either case is, cut the fat out of the hog. Meaning do a compression test FIRST. This will tell you if its a mechanical problem, or fuel / ignition problem.

Good luck, Kxpaul.