22RE missing - the last straw

I've been chasing a weird misfire on my 87 4Runner for 2 weeks. Ungh.

Symptoms: Idle misfire. Will idle cold for 30 sec-1 minute and begin to misfire. Noticeable amount of soot on tail pipe and visible (smoky)exhaust.

What's been fixed: I've replaced the cap, rotor, plugs and wires. I've ran 2 bottles of concentrated injector cleaner at low fuel in tank. The TPS checks out as per the shop manual. The injectors can be heard pulsing correctly through a mechanics stethoscope. Fuel filter has less than 3,000 miles on it. Vacuum line are OK as best I can tell. They are still soft and supple.

Strange issue: I've noticed the idle will move around. One time it will be 1,200 rpm. The next time starting it up will be 800, or 550, or 900, etc... If the air flow meter is unplugged from the wiring harness, idle returns to normal with no misfires. Plug it back in, and the misfire/stumble returns. The AFM looked like it had a dead zone when preforming a dynamic load test using a multimeter. I replaced it with a used AFM and the same issues were still there. Unplug it and the idle is fine.

What am I missing? Could a plugged idle air control cause this?

Its a Toyota and you haven't cleaned the IAC 3 times yet on general principle?

Did you check for codes? Sounds like you have a bad sensor, maybe CLT. No AFM puts the ECU into "super limp home mode."

Not sure if any of the VancePepVatozones read OBDI around here. Have to call around on Monday.

CLT is what exactly?

My money would be on a bad sensor somewhere. If it's fine when the air flow meter is unplugged, I'd start there.

Appleseed wrote: Not sure if any of the VancePepVatozones read OBDI around here. Have to call around on Monday.

Don't need a reader for that truck:

http://www.4crawler.com/4x4/CheapTricks/index.shtml#TimingCheckConnector

Code Reader for 22RE motors:

I wouldn't assume that the second air meter was good, also have you checked/ replaced the coolant temp sensor? Since you mentioned the sooty tail pipe, a failed coolant temp sensor is a common source of a rich running condition.

I once had to repair a forklift with a GM V6 that had open loop TB injection (no O2 or air flow sensors, just T/P, MAP and coolant temp). It was running so rich that there was gasoline pooling on top of the throttle valve if it was allowed to idle for more than a few seconds. The coolant temp sensor was faulty, making the ecm think the engine eas stone cold all the time.

In reply to HappyAndy:

Check both the intake air and coolant temp sensors, the old Toyota books have graphs showing what the resistance readings should be IIRC.

I reset the ECU. I've been unplugging sensors with the engine running so i regard them as false codes. Turn the key, without starting it and a code 11 is immediately thrown.

Code 11 is:

Short circuit in Check Connector T with A/C switch ON or TPS - IDL point OFF

• Defective A/C switch

• Defective TPS circuit

• Defective TPS

• Defective ECU

TPS - IDL point OFF. What do you think this means? One of the 4 prongs on the TPS is labeled the idle circuit.

As I said I tested the TPS. But I might has to adjust it. I was laying on the manifold at the time issues putting on a gasket at the back of the engine, so maybe I bumped it.

Did you make sure there are no vacuum leaks. I would do a smoke test on it.

Follow what Hess said. That's the diagnostic tool, and let the ecu tell you what's wrong.

As long as you're just flailing around, check your coolant level. The engine will do very strange things if the coolant level is low.