My 22re is suffering from an intermittent idle issue. It will idle fine sometimes, then drop really low for no particular reason at random. I can't make it happen-it has a mind of it's own. I haven't noticed it much when the motor is cold.

Browsing the FSM, the water temperature circuit comes up as the first culprit to check. I'm embarassed to say this, but I don't have any idea WHERE the water temperature circuit even is.

Page FI107 gives a diagram and ohmmeter resistance checks. I have to find the darn sensor first though.

Anyone care to help? This has been going on for quite a while but it's really getting bad now.

Thanks in advance.

Very hard to diagnose intermittent problems, except to say loose connections are probably the culprit most of the time. The water temp sensor is to the right of the cold start time switch. Both are almost directly underneath the throttle body, just 3 or 3 1/2 hairs to the right. The connectors for both are only a couple inches apart and both face forward (radiator) on my 88 truck.

Thanks Richards. I found it this morning after poking around under the hood a bit. I was going to put the multimeter on it, but the truck is running great today. I have to dial the idle back down to 'normal'. Yesterday it wouldn't idle and I had to dial it out 3 full turns. <img src="/forums/images/graemlins/scared.gif" alt="" /> I was going to just replace the sensor, but at $70 some odd dollars, I think I'll postpone until I can get a definitive answer. Damn thing is only 16 years old... <img src="/forums/images/graemlins/lol.gif" alt="" />

If the sensor is in range with the ohm check, there is no point in replacing for any reason. If it is the culprit, check the wiring very carefully, including the harnesses running close to the engine, or even over the engine. At one point, my coil/ignitor harness actually drooped enough to catch the edge of the exhaust heat shield and melted through, but on the bottom of the harness only. It wasn't visible looking at it from above. The smell of burnt plastic was what drove me to keep looking.

another thing u may want to check is ur mass air flow sensor / oxygen sensor... u can get mass air flow cleaner... it comes in a spray can the same style as a wd-40 can. you just spray it in ur mass air flow.. good luck finding ur problem.

just to share ..

my problem was the throttle body . the TB butterfly shaft bushings were/are worn .. so my TPS values are not in senc. , causing an irratic idle (sometimes) .. I havent been able to find a "good" replacement TB .. so I'm looking , and living with the problem .

>>>*The first place I check when I see this complaint is the throttle body for air leaks.

Spray a little ether around the base mounting gasket and see if the idle picks up, if it does, it could be the gasket itself......*EB

have you had any success with solving your rough idle problem? Sounds similar to mine and have ordered the engine coolant temp sensor.

My .02cents/ experience

After many months of running perfectly on a new motor on my 86' 4runner , it suddenly developed symptoms such as you describe and seems to be common to these engines. I checked vac lines , vsv's, wires, grounds, fuel presuures , pumps and sensors and the propblem just slowly kept getting worse - to the point where I was constantly adjusting the Idle just to keep it running.

One day while troubleshooting the A/C which would sometimes idle up and sometimes not and other times surge back and forth , I pulled the adjustable idle -up vacuum valve that goes to the A/C vsv and the power steering . I couldn't find any directions in the manual to test it so I huffed and puffed in and out of all the different ports and it just didn't seem like it was really working properly. I pulled the round metal cap of the top of the Vac diaphram and inspected the material and found it had a very small tear. Too long a story short, I replaced the 22 year old valve (I think around $23.00) and it cured not only my A/C problem but my idle issue also

Very interesting, Cholltero. My AC does the idle dance sometimes, too. Maybe I should take a look at this.

Since I posted (I forgot about posting and haven't been here in a while), the TB was pulled and checked, the TPS was replaced, the water temp sensor was replaced and the idle gadget doohickey thing was also replaced. It helped some, but it's still not right.

The truck drives great and seems to idle low and rough after it's warmed up. If I drive for a little bit and stop for 5 minutes and then light the truck up again, it sometimes will idle really low/rough.

A good friend of mine that has done most of the work on my truck for me lately is wondering if the mass air flow sensor is bad. He didn't do much with the truck until this past spring when the HG blew. It was rebuilt from the main bearings up with EB's Street RV head and 261 cam. We couldn't get it to idle or run right unless we opened up the MAF and richened it up a TON. I think we were at 10 clicks.

He screwed around with a few different things and I had to replace the aftermarket headers with stock and an o2 sensor anyway so we fooled around with it again after that and it's now at 3 or 4 clicks richer. Now, I don't know anything about electricity, but when he hooks up the multimeter (I guess that's what it is), the VF readings are totally out of sorts unless the AFM is screwed with so badly that the truck barely even farts. We ignored the VF readings and set the AFM to where it seems to run best.

For what it's worth, the idle issue has been slowly getting worse over the past year or two-it's not a new problem since the rebuild.

I'm not buying a new MAF from Toyota and a used one is 100 bucks. Before I put any more money in to this, I want to find somebody with a known good MAF to swap just to see if this is what the problem is. I even offered a guy my old LC headers if he would let me borrow his MAF for a few hours. As soon as I get this sorted out, I'll post up.

I would like to look in to Cholltero's discovery as well. Maybe I have 2 problems.