I have a 1995 Toyota Pickup with an idle issue. On a cold morning, the truck will start-up well...idles-up to warm-up the engine...until it completely warms-up it will idle at 750 RPM...once it is completely warmed-up it will idle anywhere from 1500-2800 RPM. With it being a manual I can control the idle...if I pull-in the clutch, coming to a stop, under 2000 RPM the truck will not idle above 2000 RPM, generally 1500-1800 RPM...if I pull-in the clutch, coming to a stop, over 2000 RPM the truck will idle at 2500-2800 RPM, while stopped. If, while stopped, I turn the truck off and back on, the idle will return to 750 RPM, until I begin driving again. The truck does not lope, just has erratic idle. Occasionally, the truck will mysteriously begin idling correctly, while warm; sometimes the idle functions correctly longer than other times. I checked all of the vacuum lines; they seem tight. Any thoughts? Thank you in advance for your assistance!

 

Let me translate that from funky fonts and run on sentances.

It starts normally and comes off of warm up idle properly? After driving it some distance it will start to idle high?

Throttle body, inspect for binding and clean. Verify the cable isn't sticking. Perform tests on the DASH-Pot and IACV.

Verify the engine light lights up before you start the engine. If it's a sticky or leaking injector you should be throwing mixture rich codes.

 

I would start with the idle air control valve. Sounds like it is sticking some times. You may just need to clean it.

 

Yes, your assumptions are correct. Last year, the truck would lope. I took apart the throttle body, cleaned it, and re-assembled it; fixed the loping. It was running great up until a couple of weeks ago.

Also, I removed the small coolant tube running to the IACV. I didn't notice any obstructions in the line. Actually, after re-connecting the tube to the IACV, I blew thru the tube and coolant spewed out of the spot where the other end of the hose goes.

 

3vze or 22re? 4wd or 2wd? How many miles?

 

22RE, 4x4, ~153,000 miles

 

Start simple and check for any kind of vacuum leak.

 

Agreed.

If you cleaned out the throttle body, there is a chance the valve inside the throttle body is sticking and not closing. This would be obvious though, since either blipping the accelerator pedal or physically rotating the valve would cause it to close. A few drops of lubricating oil would fix this. The Dashpot would be obvious as well, it's the spring loaded contraption attached to the throttle body. But if this were not working right, it would do it when cold as well.

The fact that it only does it when warm makes me that's not the issue. Sounds like a sensor is sending bad information to the ECU, causing very high idles. If you have a multimeter ($10 at Harbor Freight), check the Throttle Position Sensor (TPS), Engine Coolant Temp Sensor (ECT), and the Volume Air Flow Meter (VAFM, the sensor on the airbox). You can find the specs below:

TPS
ECT
VAFM