Code 25 and Code 26
 

Hey I have a 1995 4runner 3.0 3VZE

I checked the CEL and it gives me 25 and 26.

Now I have asked some people and they said it could be the o2 sensor.

I notice that in the mornings when I start the car, I get visible smoke from the muffler and it smells rich in gas.

Could someone point me in the right direction to get this resolved.

is the smoke black?

Yep - looks like an O2 sensor would be a good place to start. Remember - NGK (box will say NTK) or Denso only, do NOT use Bosch!

http://personal.utulsa.edu/~nathan-b...26diagnosi.pdf

No its white smoke

25 and 26 are both rich and lean? refresh my memory

if that's the case, i've been getting both those codes for YEARS, both before and after changing the o2. i've never figured out what the deal w/ them is, so i gave up. after resetting the ecu, the codes don't show up for months and the engine runs the same. meh

Have any luck with your problem? And yes codes 25, 26 are too rich/too lean.

When this happened to me it turned out that one of my vacuum lines was loose.

I still need to change this o2 sensor out of my car.

Which one do I change out? The front or the rear?

You sure you have two?

Anyways, front.

a '95 will only have ONE o2 sensor as it's an OBDI car. OBDII (96+) have 2 sensors

try cleaning out the throttle body and intake plenum w/ a can of tb/carb cleaner. i spray it down an intake vacuum hose while manipulating the throttle with my hand. i usually use a full can.

I've been having the same codes as well for the past couple of months. changed out the o2 sensor to no avail. have checked the AFM, replaced wires, plugs, water temp sensor. and still no improvement. i had changed a pair of vac lines that travel from the left side of the manifold to right under the power steering pump. that made the best improvement but it then went back to its issue. QUESTION: are we supposed to use special types of hoses to replace vacuum lines? I'm wondering if the hoses i replaced cant handle the heat and have either stretched or cracked and are now allowing air to enter again.

bumpin up

25 and 26 equals bad news, get a compression check, I had these codes and had no compression in one of my cylinders.

if one of the cylinders didnt have compression wouldnt that cause the vehicle to idle horribly?

jht3,
if the 95 is a california emissions vehicle, it will have 2 O2 sensors. one before the cat and one after. the one before is used by the computer to determine air/fuel ratio. the latter is just to monitor the condition of the cat. It doesnt affect anything.

Code 25 is lean, 26 is rich. It only means one thing when both these codes come up! A powerr inbalance. Check compression, you have a cylinder not working up to par. A compression check should reveal something or a secondary ignition problem. Secondary would be much less $$$

Well guys, i think i finally found the solution to my problems. After replacing a bad egr valve that was stuck open i noticed that the truck was runnin a bit rich. i came to that conclusion after finding it necessary to open up the idle up screw almost all the way just to get it to idle within spec. So after pondering this for a couple of months i finally rechecked my fuel pressure. As before, it was running at about 44, 7lbs over spec. since i was using a cheapo harbor freight fuel pressure tester i thought maybe the tester was off. so i went ahead and checked the VSV ( god thats a bitch to test). well the VSV was working fine so i finally broke down and got a fuel regulator. out with the old and in with the new and WALA!! No more codes! I would have never thought that a couple of lbs would have made such a difference but it did. Fuel pressure's now within spec and I'm a happy camper.

Guys, thanks for all your input on this forum! The knowledge you guys share here is a blessing to do it yourselfers like me.

So I've been having the same problem and gave up a while ago but started driving it again and figured I would take another go. I like the fuel pump because I was just thinking probably at 326,200 original miles, it could be going out....stay tuned 👍😁