High Idle When Warm

[BayareaEMT]

Hi Guys,

I am a newbie to this forum. I usually do all the maintenance for all my cars at home with help of my cousin. Recently I bought a 98 ES300 with about 110K on it.

I decided to do full servicing since I didn't get all service records from previous owner. Car had been running good though since I bought it couple of weeks ago and also it was running perfectly fine when we did following.

Engine Oil and Filter change (Mobil-1 oil & filter)

Transmission Flush

Radiator Flush

Brake Fluid Flush

Power Steering Fluid Flush

Spark Plugs replaced with double platinums

Spark plug cables replaced

Air filter replaced

Replaced front brake pads

Tire rotation

But yesterday after we did throttle body and intake cleaning since then car starts up with over 2000 RPM and stays high (1700+) RPM even after it is warm (2+ minutes). I took a ride on freeway and even after 10 minutes of driving if I live the gas pedal car keeps cruising at 45 MPH and doesn't go below that range. And because of the higher RPM, tranny doesn't shift smoothly. It shifts fine while in motion but I feel little jerk while going from Park to Reverse or Drive.

We didn't remove the entire throttle body out but just removed the big flex hose that connects to throttle body opening and then sprayed with STP cleaner and used clean cloth to clean inside. My cousin did lift the butterfly opening while car was not running. Can this cause problem? And if yes then how can I get this fixed?

Does anybody else have seen similar symptom?

I will really appreciate your help regarding this matter.

-EMT

[Toysrme]

Reset the ECU (Pull the EFI fuse for a second & replace it).

If it doesn't get better, check the coolant temp sensor.

[BayareaEMT]

Reset the ECU (Pull the EFI fuse for a second & replace it).

If it doesn't get better, check the coolant temp sensor.

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Thanks for info Toysrme..

So you think that the throttle body cleaning has nothing to do here. One question I have is does this car have fly-by-wire system for throttle control in 1998 model. If it is equpped that way then is it ok to move butterfly plate with hand when car is turned off? I was somehow being told by someone that you should not touch butterfly plate for fly-by-wire cars otherwise TPS adjustment gets shifted and it is very hard to set it back unless you take it to dealers.

anyways, I will try to reset ECU and also check the ECT sensor to see if it functioning normally or not. One question though for resetting ECU. Will this cause any problems with radio lock-out? I think I have anti-theft radio and I didn't get the secret code from original owner. I will try to find out.

[Toysrme]

No, you won't have any trouble. The EFI fuse cuts the power to the computers. Everything else keeps power. (Radio clocks, ect)

No, no drive by wire.

New change of plan since I re-read the first post.

Between the high idle (Open Throttle plate) & funny shifting pattern. It sounds like there is extra tension on the throttle cable & the transmission kick-down cable.

What he did was change the tension on the cables when he took them off. Look back to my quicker transmission shifting guide as a visual aid on what's happened.

He probably has the throttle cable tightened too much so that the plate never closes. This also keeps added pressure on the kick-down cable lowering the amount of throttle it takes to *BLEEP* & stiffening the shift some.

[BayareaEMT]

Thanks a lot for info Toysrme.

Where do I find your quicker transmission shifting guide as you mentioned in your post above? Where is transmission kick-down cable located? I don't think we touched any of those cables since we didn't remove throttle body out.

You have been really helpful.

[Toysrme]

http://us.lexusownersclub.com/forums/index...ssion++shifting

Make sure the cables are in the middle of the road adjustment. If you have to, take the pipe off & make sure the throttle plate is in a closed position.

[BayareaEMT]

Finally I was able to get it working fine once again.

I tried the stuff mentioned by Toysrme but those didn't work.

After I cleaned MAF sensor it started working again. Now my idle stays around 700 as it used to be when I bought the car.

Looks like something happened while we disconnected MAF to remove the hose assembly going into Throttle Body.

Thanks for you all your help guys.

[Toysrme]

Awsome!

Where's sk when you need him?

[91L3xus]

Awsome!

Where's sk when you need him?

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LOL

[Toysrme]

Ah come on that was hillarious LoL!

Gotta be able to admit when you didn't pin it down. ;)

[91L3xus]

Ah come on that was hillarious LoL!

Gotta be able to admit when you didn't pin it down. ;)

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Oh, don't worry, I know what you were referring to. ;)

All I had to do was read your Free Mod Series threads.