Benjamin T

iTrader: (2)

as per the instructions, he took it completely off. and yes everyone, tapping the screws with a hammer and screwdriver does work in loosening those stupid soft screws.

the mechanic did not run the engine with the black part off. he did try to turn the round fitting by hand to see if it was stuck while the car was not running and he said there was movement, but we weren't sure how much movement it was supposed to have.

with the engine off and the black part bolted back on and the wire harness not plugged back into it, he ran power thru a jumper directly off the battery to the pins in the plug on the black part as the service manual, and we can hear the electromagnet close, but when he reversed the connection and jumped to the next pin, there was no sound indicating it was open.

i think that's exactly what i he did. he was trying to get a reading but the values were all over the place.... the lowest on one side was 1 ohm, and on the other side it was as high as 60 ohms?

he used throttle body cleaner and then blew it out with compressed air... no change.

give me the procedure please. if you have pics that would be a bonus too...

Benjamin T

iTrader: (2)

i need to add something... when coasting on a slight to moderate downhill grade (ie. in gear, but not on the gas, holding a constant speed), the engine starts to surge, as in the car accelerates/decelerates on it's own with the rpms jumping roughly 500rpm in either direction. stepping on the brake makes it stop. this surging also happened only once at a stoplight. i was lightly on the brakes when the first surge happened and the car pushed over the stop line before i could catch it

code58

Benjamin- When you say you step on the brake and it makes the surging stop, do you mean it stops as long as you stay on the brake, or it stops surging if you just step on the brake and then let off? I am beginning to suspect a vacuum problem. The book does address an "air assist system". To check the IACV operation with it off but still plugged in as I outlined... turn it up so you can see the cylindrical valve. The side that takes the air in should be half open. Have someone turn the ignition to ON (not start). The valve should move to fully closed, fully open and back to half open, all either in .5 sec or .5 each, it's not exactly clear but I assume all 3 in .5 sec. Book says if it doesn't do that, it's bad. I'll leave that decision up to you. If you try that and it work that way, I'll try and research the "air assist" and give you that info. Sorry for the fact i'm technologically challenged in knowing how to post pictures. I'll have time to learn one of these days!

Benjamin T

iTrader: (2)

it stops surging if i just step on the brake and then let off.

Benjamin T

iTrader: (2)

the mechanic says he wants to replace the IACV. he called the local lexus dealership and they quoted over $600 for the part(s)???



does anyone know where i can order the part(s) cheaper and will ship to canada asap? i also need help with part numbers?

code58

Benjamin- I can't give you all the answers you need, being in Canada, but I'll give what I have. One of the best places I've dealt with is called Partsgeek. Add. is www.partsgeek.com They are in N.J. I believe. They show retail as $248.47 and their price as $175.75 Their shipping rates are very reasonable. This is an Aisin (Lexus original equipment) IACV. Go to the site and you can get the phone # there. I have no idea how things work between here and Canada but you can ask them that. Good Luck!
You have to buy the rubber gasket separate (same with everywhere), but when I replaced the one on my DIL's RX, I used the old one which was in perfect shape and have had no leaks or problems at all in 3 1/2 years.

carguy07

Carson sells it for $206.23 and ships worldwide.

http://www.trademotion.com/partlocat...&siteid=214915

salimshah

IACV is where the rubber meets the road for idle control, but the problem can originate some-where else.

Also it can be as simple as replacing the diamond marked gasket [specially if the idle problem started with messing with IACV. Can you you also give us history ... was the idle ever good? What happened before it went bad.

To check for vacuum leaks, you can try spraying carb cleaner around vacuum lines. [even around the diamond marked gasket]. If the idle shoots up, look for cracks.

If every thing else fails and you can not figure out what is going wrong, you get into the mode of start replacing things one by one and then changing the IACV would be the first logical choice [Your mechanic may be at this point].

Salim

Benjamin T

iTrader: (2)

thanks. i put out a lot of email inquiries (many places have a 1-800 number that dosen't work outside of the US, usually a sure sign for me they won't sell to canada), and i've ended up going to http://www.lexusparts.com because they were the only ones who answered my messages, where they have the IACV for about $195 and will ship to canada... but i'm waiting for stock.

unfortunately it costs $60 to ship to me standard ground (at least 5-7 business days)... $180 if i want to overnight it. argh.

Benjamin T

iTrader: (2)

salim,

sorry for the late reply. i could not log onto this site for 2 days for some reason

i've pretty much explained everything that was done by the mechanic who is looking at the car to diagnose this. he's followed the diagnosis procedure as described in the shop manual and the IACV is not closing in accordance to the tests required (ie. ignition on without starting, and observe if the valve cycles). it's taken the mechanic 4 hours to reach this point

the idle has been "good" up to now. at most, it's a bit low at time, especially if all the accessories are on (except for the a/c, which raises the idle). when this first started last month, the shift points seemed off, and sometimes i wouldn't get overdrive/4th. and then there was the big clunk when coming out of park and between reverse/drive. i mistakenly thought it was the beginning of transmission problems, but when i brought it to the mechanic he saw right away there was something wrong with the idle.

does anyone know if in order to change the IACV, does the throttle body have to be removed?

Lexmex

Yes and know. The manual calls for it, but I've known others who have been able to get at the four screws directly underneath the throttle body and behind the black piece. In that diagram above you can see one of the screws at the bottom of the picture, if you're folloing along from the service manual it's in the SFI section, page SF-43. Again, you'd need a very small phillips head and it can be a PITA, but yes, it's possible to do without removing it.

99gslexus

i have a idle problem too. i just changed my spark plugs and cleaned my throttle body. and now when i start my gs300 in the morning it idles around 1800rpm. it takes 7 minutes to idle to 900rpm. how can i readjust the fast idle?