Code 26 Air Fuel Ratio Rich Diagnosis

[RrCoX22]

Just picked up this rig 2 weeks ago and its now sputtering at idle almost like misfires and no power under acceleration with lag and jerks. We got heavy rains and believe the O2 sensors may gotten wet as previous owner mentioned he never really drove it in the rain. Am I onto something with replacing the O2 sensors as the exhaust seems to all be original. Any other ideas or insight? Don't feel it's plugs as the engine was just rebuilt 4k miles ago with new plugs and wires. Bad air flow meter would be similar to the symptoms as well and would need to test. Thanks for any help.

 

[Rifleman]

Read post #13 in the link below, i had a problem with water in one of my O2 sensors that caused a problem like what you're experiencing, hope this helps,

No check engine light, ruff idle problem

I've run into a intermittent ruff idle problem the past few days, but do to limited time i haven't had a chance to trouble shoot it yet. I'm working with a 1994 Land Cruiser. So far the problem seems to only cause the idle to drift up, and down between 650, and 475 RPM while in drive, with AC...

forum.ih8mud.com

 

[OffRoadScott]

Before you replace the o2 sensors check the resistance. Per the FSM they should be 5.5-6.0 ohms. I was dealing with both a high HC/CO and once I replaced my O2 sensors (resistance was 13 + ohms on both) it fixed the issue and I was able to pass emissions.

One other thing to check is the wiring harness near the EGR. The EGR is known to melt the harness and cause shorts which would give you drive ability issues like you are talking.

This is what mine looked like, visually looked good. But when the LC idled the harness was moved around and made a difference in the way it idled.