3fe code 25/26

[mr jits]

Popped up today. Running too lean and too rich at the same time? Runs fine with no symptoms anywhere in the power band.
I haven't touched anything in the engine in ages, so some guidance would be great.

 

[jonheld]

My first instinct is to remove the 15amp EFI fuse for 10 minutes or so and let the ECU clear out and reset. If the codes persist after that, then my suspect would be O2 sensors.

The FSM also suggests injectors, FPR, AFM, cold start injector in addition to the O2s.

 

[mr jits]

I'll check to see if the codes persist this morning (pulled the efi fuse last night). If so I guess I'll be spending some time with the ohm meter.

 

[Smplybttr]

What was the outcome? I just had both codes pop up and I'm shuddering a little at stops. Out of the blue...

 

[mr jits]

I desmogged and it all went away.

 

[WarWagon]

Mine came with the cats already removed.....what else would I need to do to desmog all the way?

Will this affect detecting issues in the future?

 

[mr jits]

There's a desmogged thread running around somewhere. Basically you remove all smog related parts.

 

[FJ80 Money Pit]

On the 3FE error code 25 & 26 is due to a vacuum leak, block or a vacuum hose disconnected. This causes the EGR to remain open during idle and coasting when it should be closed and causes the fluctuating rpm under 1000 and error code 25 and 26, because with the EGR constantly opening and closing the fuel air mixture to fluctuate between rich and lean.

1) check the throttle body vacuum out lines on top, make sure theyre clear and clean with a needle in a pair of vise grips from the bottom and spray cleaner in the holes from the top.

2) check the two metal lines under the intake from the throttle body to the egr modulator with a vacuum guage. If blocked run two vacuum line from the throttle body to the egr modulator, one to P and the other to R with a split tee to the BVSV. These two metal lines always rust out on older trucks and causes blockage.

If you think its the O2 sensors then remove, unplug, clean with mass air flow sensor cleaner and reinstal with new nuts.

 

[proteolytic]

On the 3FE error code 25 & 26 COULD BE due to a vacuum leak, block or a vacuum hose disconnected. The other reasons posted in the FSM are still valid. I had the same codes and it was my AFM.