kb2yza

A clogged Fuel Filter would also cause drivablity issues similar to a clog fuel injector, whereas at full throttle the with a clogged filter would only have half the fuel pressure cause a dribble into the cylinder


Removal

1 Remove throttle body

2. Rmove IAC (4screws into bottom of TB)

Located on under side of TB, has a 3conductor connector on front and an air hose going into bottom. During removal you will be taking out 2 gaskets these are not reusable.

pilsun10

kb2yza,

Can you provide me detail info? I am a rookie when it comes to car maintenance. Is this something a rookie can fix or should I take it to the pros. If you have any pics to show where it is located that would help me a great deal. Thank You

pilsun

Francis

Same problem here.
Solution: Dealer replace idle speed control ($400) last week. And problem solved. I think Lexus should have a recall for this since a lot of RX owner have this problem.



Francis 99' RX (78k miles)

HarrierAWD

Dunno. According to CR's owner survey, less than 2% of the RX owners reported engine problems. That's for every model year from 99 to 03. No engine is bullet-proof, but this is a good track record IMHO.

SilverSprt

Yup..this is what I have been hearing. The solution seems to be to clean the IACV/throttle body. I am experiencing this problem. You'll notice that for some users this happens when your car is still warm. Say you've driven your car to work and leave it parked in the sun for 15-20 mins. When you come out and start you car it stalls and dies out unless you give it some gas. This is what happens to me, and it doesn't happen 100% of the time. I have not cleaned the IACV /throttle body yet as I haven't been able to find a step by step post. I talked to Fremont Lex and they don't clean these. (They claim in won't resolve the issue) Stevens creek lex does for about $180 (labor only). Let me know if any of you guys have any further insight.

MellonC00

Same problem here. An independent dealer changed the Idle Air Control Valve/Throttle Body. The part alone was $219. Adding labor to hunt for the problem added another $375. Grant total was about $590.

Did I get ripped off?

Lexmex

The labor does look suspect. I think my U.S. Lexus dealer was charging me about $80 per hour.

SilverSprt

Idle air control and idle speed control...are those two terms synonymous or are they two unique items?

On this forum they many refer to IACV, however when I went to the dealership they referred to it as "Idle speed control valve"...

Lexmex

In the service manual, I see a reference page to Idle Speed and a separate reference to IACV.

In the section on Idle Speed, they state that if the idle speed is not as specified check the IAC vavle and air intake syetem

Bobk528

During the past month, my 2000 RX300 with 69,000 miles was having difficulty starting up particularly on warm afternoons. One afternoon, it would not start after repeated attempts, however after several hours of rest, I was able to start it although it would shut off if I let off the gas pedal. Once on the freeway, it ran nicely. The next day, I took the vehicle into my mechanic who discovered that the magnet for the IACV was so heavily gummed up, he was not able to move it. The repair bill came to $135 to clean the IACV. My mechanic indicated that a Toyota dealership typically will replace the IACV instead of cleaning which is quite an expensive part but he stated that the IACV gums up about every 60,000 to 80,000 miles and there is no need to replace them – just clean it every 60,000 miles. After I picked up my RX300 and drove it onto the freeway, I immediately noticed a big difference in the response, smoothness and power. I have read other threads in the Lexus Forum about IACV related problems and some attempt to fix the problem by putting in a fuel cleaner into a tankful of gas. The IACV does not receive fuel but takes in air and can only be cleaned by removing the IACV.

Lil4X

Wow! Nice catch Bob! Thanks for posting.

Lexmex

Looking in the manual again and looking at the IACV in my engine bay, this doesn't seem to hard to take off and give it a thorough cleaning. If I get some time this week, I will do it and post some pictures.

The reason this interests me is twofold: 1. I don't use an air filter and would be interested to see how much gunk is there and 2. My main weakness on the track are the launches, i.e., 60 foot times, and when I hit my record 17.931, I distinctly remember a higher than normal idle when I launched on that record run. I hardly give it any gas when the staging lights start flying based on experimentation, so better idle air would be a plus.

Thanks for the info Bobk528.

Lexmex

This is a picture of that valve.

I am going to play with it tomorrow and will post pictures after I am done. Was going to do it tonight but my cousin got a little too antsy as his Unorthodox Racing Pulleys came in for his Golf.

Bobk528

I asked my mechanic about whether a carburetor or throttle cleaner could be used and he stated that because the IACV contain nylon he uses a different type of cleaner. I did not ask him what type of cleaner he used to clean my IACV. When I went to the auto parts store the other day, there was a cleaner especally made to clean the MAF. I wonder if this product could also be used to clean the IACV?

Lexmex

Bobk528,

I have sprayed a few things in this area before, including carb cleaner and a water mist spray. The carb cleaner flew out the tailpipe at the the back and I had no issues with it. Something that cleans the MAF is probably a safer bet, though I now recommended electrical contacts cleaner only for the MAF (both the red diode and the wire), though I had use brake dust cleaner previously for the red diode.

However, this will be the first time I actually take IACV off to see if there is any other gunk I haven't reached before.

I will ask my uncle his opinion based upon what type of material accumulation we see inside.