Warm High Idle INSANITY!!!!!

[Txwelder]

1993 4Runner, 22RE. Im at the end of my rope with the high idle when warm and the fluctuation at stop lights with the brake pedal depressed. When I start the truck it idles at about 800 RPM. Once it warms up, it idles at around 1400-1700 RPM until I step on the brake and then it bounces up and down. Here is what I know:

-TB has been removed and cleaned.
-TB butterfly seems to have excessive gap between itself and inside the TB cylinder. Also side to side play in the shaft.
-Idle screw is all the way in.
-TPS has been checked with a multimeter and it's good.
-IACV has been completely blocked off, not just the hoses, but a plate between it and the remainder of the TB.
-New Coolant Temp Sensor.
-Multiple cans of carb cleaner sprayed on every inch of the engine to find a vacuum leak with no luck.
-Timing has been set as close as possible with idle a little high.

Im stumped and leaning towards the TB being bad but dont want to drop $225+ to shotgun a part at this truck. I really hoped the IACV block would have solved my problem but it didnt. With that blocked and the idle screw all the way in, all I know is its getting air from someplace and the gap between the butterfly valve and the TB cylinder is all I can think of. Any and all help is appreciated.

 

[Txwelder]

With the TPS unplugged, I don't get idle fluctuation when the brake is pressed.

 

[KidVermicious]

Your idle is too high. It bounces when you hit the brakes because the computer momentarily cuts fuel to the injectors, then restores it, then cuts it, etc.

Where's your throttle stop set at?

 

[Txwelder]

I cant tell you exactly where it is set but I set it per the 4Crawler page when I tested my TPS.

 

[KidVermicious]

I cant tell you exactly where it is set but I set it per the 4Crawler page when I tested my TPS.

Cool. If that's set correctly, then it sounds like it might be time for a throttle body rebuild, or a new unit. I think your idle is high because you're getting more air than the TPS is expecting based on the throttle position, and that's probably because of the slop you noticed at the butterfly. There shouldn't be any.

 

[Txwelder]

Do you think that it is heat related? When I started my truck this morning it idled perfect at 750 then when warmed up it shot up to 1500 and bounced when I was on the brake, just like every time I drive it.

 

[KidVermicious]

Do you think that it is heat related?

Nope. When the truck is cold it's in open loop and not paying attention to input from various sensors.

 

[wallytoo]

Nope. When the truck is cold it's in open loop and not paying attention to input from various sensors.

and therefore it is heat-related, indirectly.

the warmed engine isn't the cause of the problem, but the problem won't manifest itself unless the engine has warmed up.