High Idle Immediately After Starting... 99 Es300

[yaj786]

Hey all, even though I've been a member for a few years now I haven't really posted a question yet.

My 99 es300 idles loudly at about 1100 rpm as soon as I start the car (not cold, its summer)... it is really noisy and it makes me cringe... however as soon as I put it in reverse it drops to its normal ~600-700 RPM... and it never does it again, even at traffic lights.

So basically the problem is only RIGHT after I start the car and still have it in park.

I've been looking around the site and I'm thinking it could be the throttle body that needs to be cleaned? I'm a complete car noob so I'm not sure if that's right.

If anyone has any suggestions or guesses it would be appreciated.

Thanks!

[TomWoodLexus]

When cars come on the shop with this problem, I always do this right from the start:

1.) I forst sell a cleaning of the intake with a cleaning of the Idle Air Control valve. It is all labor, one hour. Very cheap.

2.) Pull the upper portion of the air filter box off and start pulling pieces of the intake off untill you get to the IAC. The IAC is just under the part of the intake before the throttle plates and is mouted on the bottom of the throttle body. Inside the throttle body you will see an orifice on top of the IAC where air is let in to be bypassed of the plated to control IDLE.

3.) Next, pull off the stpper motor from the actual valve, it has 2 screws, they are tight and easily strippable, so make sure to put FORCE into the screw and use the correct driver.

4.) With a good throttle body cleaning solution (auto parts store, in a can, spray into the !Removed! while turning the valve back and forth. You will notive it freeing up instantly. Also open the throttle plate and spray some into there ans scrub as much of the intake as you can to clean it.

5.) also, under the IAC there is a hose going down, disconnect it so some of the cleaner can escape so the car won't have to try to burn it. And make sure to let the car sit for 5 minutes with a driver inside the body holdingthe throttle plate open to let some of the fluid evaporate so that a slight chance of hydro-lock will be impossible.

5.) put everything back together and make sure EVERY connector is back on and all the vacuum hoses are back on and start the car as so in step 6.

6.) Starting the car is hard with all that crap in there, so put the car in clear flood mode by giving the car 100% throttle and turn it over untill it starts. In clear flood mode the computer notices that the voltage from the TPS is high and will not pulse the injectors (usually anything above 3.5V) and when the engine does more than 300 RPM's than it will pulse injectors. That is why when it fires it will rev up. It may run rough for about 3 seconds. After that I usuallt let the engine sit at 2000 RPM's for 10 seconds to let the high amount of air flow suck everything dry and voilal! High idle is gone.

Sometimes the high idle stays, further diagnosis is required, but we can get to that later if that happens.

[homemechanic]

Hi. I need a little help here. I was able to remove the throttle and cleaned the IAVC. However, I am still getting a high idle at cold start. It's idling around 1500 rpm when I turn the car on and drops to 600-700 rpm when the car runs hot. Any other suggestions?

Thank you!

When cars come on the shop with this problem, I always do this right from the start:

1.) I forst sell a cleaning of the intake with a cleaning of the Idle Air Control valve. It is all labor, one hour. Very cheap.

2.) Pull the upper portion of the air filter box off and start pulling pieces of the intake off untill you get to the IAC. The IAC is just under the part of the intake before the throttle plates and is mouted on the bottom of the throttle body. Inside the throttle body you will see an orifice on top of the IAC where air is let in to be bypassed of the plated to control IDLE.

3.) Next, pull off the stpper motor from the actual valve, it has 2 screws, they are tight and easily strippable, so make sure to put FORCE into the screw and use the correct driver.

4.) With a good throttle body cleaning solution (auto parts store, in a can, spray into the !Removed! while turning the valve back and forth. You will notive it freeing up instantly. Also open the throttle plate and spray some into there ans scrub as much of the intake as you can to clean it.

5.) also, under the IAC there is a hose going down, disconnect it so some of the cleaner can escape so the car won't have to try to burn it. And make sure to let the car sit for 5 minutes with a driver inside the body holdingthe throttle plate open to let some of the fluid evaporate so that a slight chance of hydro-lock will be impossible.

5.) put everything back together and make sure EVERY connector is back on and all the vacuum hoses are back on and start the car as so in step 6.

6.) Starting the car is hard with all that crap in there, so put the car in clear flood mode by giving the car 100% throttle and turn it over untill it starts. In clear flood mode the computer notices that the voltage from the TPS is high and will not pulse the injectors (usually anything above 3.5V) and when the engine does more than 300 RPM's than it will pulse injectors. That is why when it fires it will rev up. It may run rough for about 3 seconds. After that I usuallt let the engine sit at 2000 RPM's for 10 seconds to let the high amount of air flow suck everything dry and voilal! High idle is gone.

Sometimes the high idle stays, further diagnosis is required, but we can get to that later if that happens.

[TomWoodLexus]

Shoot. I am an idiot. I guess I never read how many RPM's you said it was! 1500 is perfectly normal. It is like that by design, colder engines need higher RPM's. Not only to be able to run itself and not stall, but to warm the engine quicker so that the cat heats up so that emmisions can be FiReD sooner by the cat.

[homemechanic]

Anyway, I guess I don't need to work on the car anymore if running 1500 RPM at cold is normal. After I cleaned the IAVC and throttle, it's running more like 1700 RPM today because the temperature dropped to around 50F here. The throttle and IAVC hasn't been cleaned at all for 120K miles because I bought the car used. My gloves were like charcoal after cleaning that stuff out with brushes and cotton swap. I guess I don't need to worry now.

By the way, I had a good lesson on taking out stripped screws. The IAVC screws are pain in the a$$ to take out. I stripped two screws in the process. I used a wheel cutter and tried to make a grove for the flat head screw driver, but no luck with turning the screws. I ended up using a pair of vice grip to turn the stripped screws.

[TomWoodLexus]

Yeah, those screws are pretty seized up, I've one so mayn that I know now to put all my body weight into them to unscrew them. It is good that you cleaned that out anyways! It is a great service to have done. Keeping the build-up to a minimum is always good.

Another good service would be to clean your MAF sensor. Just get a spray from a local auto parts store. There is such thing as a mass airflow cleaner out there. Sometimes people have cars than run a little rough at times, or hesitate from a stop. A good way to test this is to put the car in park, quickly depress the gas pedal and let off, it should go up in RPM's almost instantly, if it hesitates than that is a dead give-away of a dirty MAF sensor.

[chris177]

my 99 es300 goes to 1900 rpms when cold, then down to 800 when fully warmed up, and its still in the 70's here. Thats after cleaning the iac and maf and tb well. just bought it last week i dont know if its normal or not....

chris

[yaj786]

Thanks for the info!!

I think I'm probably just going to take it to a mechanic... how much should I expect to pay?? I don't want to get ripped off.

[TomWoodLexus]

How much for what? A cleaning is one hour, which at my dealership is $100. VERY good sevice and well worth the money.

[homemechanic]

If you don't know how to take the throttle and IAVC apart, good idea to go to a shop and have them cleaned. An hour of labor is FAIR. Consider I took three hours to dissemble, remove two stripped screws, clean and re-assemble. I also invested in a small short handle ratchet to get the nut off the bottom of the throttle.

That hour of labor you paid is well worth the quiet and smooth idle and acceleration. The shops in the west here charge more than $100 for this service.

[adil]

hi its my lexus es 300 1999 when i start my car its good but after it get warmed the rmp goes 1000 to 1400 rmp continusly after 2 or 4 seconds i dont know what to do after that some one told me to clean the throttle with fuel injector but not worked i dont know what to do and yes! my air intake pipe is torn from the starting is this is the issue ?? dont know what to do anyone can help me??

 

[dominque]

Hi,I have a 2000 and a 2001 gs 300 lexus.The 2001 has a high idle when start up in the morning and after sitting for a while.The idle is high until the engine is warm.It don't matter if its 100 degress outside.The 2000 cranks up fine with just right idle at all times.So I switched the throttlebody from the 2001 to the 2000 car but still got the same results.Could the computer be bad or need reprogramming on the 2001 gs 300 with the high idle?