Please Help... Idle issues

[Deafcoyote]

94 4Runner SR5 3.0 Automatic 138,000 miles

Was getting codes 71, 25, 26

10k Ohm resistor in ERG Temp Connector

New valve cover and intake gaskets, Plugs, Wires, Distributor cap and Rotor, Fuel Filter, Injectors, "repaired" leak in large hose from filter to throttle body, cleaned throttle body, mechanic unable to find any reason for the low idle.

"Good compression on all cylinders"

Idles normal until warm, then holds at 700 RPM in neutral or park, 450 RPM in gear. When cruising at 40-45mph @ 1500 RPM in Over Drive stutters when gas pedal used to maintain speed.

Died at a stop light, almost died going down the road at 60mph (felt it stop, and catch back up like a stick being push started.

Now getting code 25.

I'm not a mechanic by any stretch of the imagination, but I can troubleshoot change parts fairly competently, provided I have a starting point.

I greatly appreciate any ideas of where to turn. I am currently stationed in Germany, so parts stores for North American spec vehicles are non existent. I'm also starting to lose faith in my mechanic.

 

[KidVermicious]

25 is a lean condition, right? That plus the cutting out and stumbling while driving makes me think a fuel issue. Fuel pump, fuel filter, bad/clogged injectors, bad voltage to injectors? I don't know which is more likely on the 3.0, but that's where I'd start looking.

Thanks for serving.

edit to add - here you go:

25: AIR/FUEL RATIO LEAN INDICATOR--LEAN SIGNAL SENT TO ECU FROM O2 SENSOR
--INJECTOR FAULT(S)
--FUEL PRESSURE
--OXYGEN SENSOR
--AIRFLOW METER OR MAP SENSOR
--IGNITION
--ECU

 

[Deafcoyote]

Fuel filter and injectors were changed last week. All injectors are firing and getting fuel to cylinders. I haven't checked the pump, since it only happens when in gear and runs fine in neutral. Pump doesn't seem logical, so that means it's probably the problem. Engine problems never seem to have logical solutions.

 

[giro]

If the O2 sensor hasn't been replaced recently, that might be a relatively simple (and pretty common part that's not too expensive) to replace. I've replaced a few on some other cars years ago, but my '92 at 160k might still have the original on it. If it was replaced, it would likely have been 85k ago.

I think the '94 still just has one. If you don't mind splicing in the harness, it should be pretty universal.

 

[giro]

Ok, '92 FSM is open for a 3.0 for another post, so I decided I'd check. error 25 is lean, and 26 is rich. Even if you aren't seeing 26 right now, I'd probably first focus on things that have both. BTW, my FSM says error 71 is only on CA versions, though that might have changed with '93 or '94 since I think they were slowly adding more and more emissions to all versions.

Both 25 and 26 list a "Engine ground bolt loose" as the first possibility. There's several other dups, including "Open in E1 circuit", "open/short in injector circuit", "Fuel line pressure", "open or short in the oxygen sensor circuit", "oxygen sensor", "water temp sensor", "air flow meter" "ECU". In the 92 FSM, more info is on pages FI-132 and FI-134.

If you don't have a FSM, download one using the permathread at the top of the classics section. Or use the Webarchive link SV-dude just posted for an archived online FSM for a '95, at http://web.archive.org/web/20080731...nr/Toyota.4Runner.1990.1995/files/repair.html

 

[Deafcoyote]

Update:

I found that the intake hose to the throttle body was virtually destroyed. Replaced with a new hose and cleared the codes. Idles better (but still not right) and the motor still cuts out for no apparent reason. Sometimes at a stop light, sometimes going 55 mph down the highway.

4 days later the CEL is back with code 25. I'm hoping to get it in the shop this weekend ot check the fuel pressure and compression myself. I have a feeling the problems are probably in the fuel pressure regulator or pump.

If I can't isolate the problem I may have to send her to the junk pile. Inspection is due on 22 July and I'm really tired of throwing good money after bad.

Parts alone aren't cheap and the fact that most companies charge extra to ship to APO locations and they take 6-8 weeks to arrive really adds to the frustration.

 

[jgilk1]

I haven't checked the pump, since it only happens when in gear and runs fine in neutral. Pump doesn't seem logical, so that means it's probably the problem. Engine problems never seem to have logical solutions.

there would indicate a possible concern to check the pump as every thing works until you put the engine under load and the fuel system starts to actually pull more fuel the engine runs lean so the fuel map requests more fuel and sprays a little extra you let off the gas completely or just a bit to maintain speed at a stop light the engine goes lean and putters out... going off the codes others have posted 25/26 being lean and then rich... this would be a good indication to me.. that and with the mileage and other fuel related parts you have replaced might as well pull the pump and check it.... and thank you for your service

i think wide band o2 should be required on all new vehicles as well as the obd what ever generation (they tell you more about your engine then 500 sensors do)