saudiboy

Thanks.

Interesting. So, I did the IACV and the MAF cleaning and pulled the EFI fuse. The check engine, etc., lights went off. Car starts (not great, but first time) and idles fine but when I step on the gas it sputtered. However, it seemed to go away (at least in park, after a little while).

I must say. I've got 190,000 on this car. I lost a tranny and my right side door actuator is shot, but I haven't done much of anything to this car other than abuse it. It's been the most reliable thing I've known the last 10 years.

saudiboy

This turned out to be my fuel pump. Didn't want to do the work myself; the total was $390, and my RX300 is its old self again. This car refuses to die.

DRACO A5OG

Thanks to Tcheung86 and LexMex!

Just did this service with my buddy on his 2002 Rx300.

For the last 5 months he had miserable low idle issues. It would just stall when cold and if he got it to stay started he had seriously rough idle and when driving it felt like his transmission was shot or when his ac kicked in it would stall while at speed.

It was a simple service, carefully removed the two screws, watched for the compression washer, disconnected the vacumm hose and sprayed cleaner while rotating the icv internal mechanism, sprayed some lube, cleaned it up and put everything back together, BLAM!

Started like a charm and maintained proper idle even with AC on. :-)

Baetke

A couple of tricks I have used to get stuck screws loose.

1) a drop or 2 of liquid wrench between the head and its seat, or in this case between the IACV flange and the throttle body, cuz that where the threads are.

2) If you can't loosen the screw, try tightening it. I know that sounds crazy but trust me, it works. Just rock the screw, tight, loose, tight, loose, etc... If you can get it to move at all, the penetrating oil will find its way in and do its magic. Be patient, persistent, and add more penetrating oil. Sometimes it pays to walk away and let the oil soak in for a while.

I have removed hundreds of stuck screws on airplanes and this technique has worked great for me.

(28 more to go...)

pbonck

Had the typical problem about 10k miles ago. With now over 150k the problem came back. So I took the breather down and started to clean the IACV again. After everything seemed to be working as advertised. The valve only rotated 1/4 turn as it should, very easily. I had no problem with the screws and didn't lose the o-ring. Now it idles around 2000 rpm and there "is" a little slack in the throttle cable. I'm next to positive it's an air mixture problem but I can't seem to find out what's wrong. It does sound as if it's sucking way too much air and the fuel is being supplied to keep up. New air filter to boot. Any suggestions?

salimshah

Go through the motions again.

Salim

Baetke

pbonck

Are you sure you reconnected the vacuum hose? 2000 rpm is a very high idle which sounds like an air leak into the intake manifold.

Baetke

pbonck

Thanks for all the advice. You guys are the best. Not only did I go through the steps again but I took off the throttle body and took the IACV completely off and cleaned it inside and out. It did look clean and was free in movement. Once I was able to clean behind the butterfly valve it appeared to work a bit smoother. I'm thinking a small deposit got lodged. After it was put back together it purred like the kitten she is. 151k miles and going strong. Thanks again for the great advice.

carlover

just did this on my 2000 es300 with 335k miles when p0441 and p1354 appeared after my fiance drove my car for a few weeks (as I was working on her Honda Element...not fun to work on) and put cheap gas with ethanol in it. The throttle body cleaning was something I never heard of, and after a bit of seafoam in the gas tank and oil pan, an oil change and some premium chevron/texaco gas with lucas oil upper cylinder lube I performed the cleaning. Worked like a charm. y'all rock!

I've heard from a lot of people ethanol ruins plastic / rubber parts by hardening them prematurely, but the fact that my es300 with all these miles got codes so quickly after she drove a few tanks of cheap kroger gas thru my car makes me worry. anyone know how to find gas stations with no ethanol? anyone else heard of symptoms caused by this ethanol gas? I wanna get another few hundred thousand miles outta this beast!

imherenow

cleaned IACV few days back and was ease especially when the 2000 ES models have the similar engine design as RX. But i found the PCV very hard to access on the RX.

JohnnyO23

Great write up. Good pic's. My wife and I purchased our first Lexus in August. A real creampuff (2002, RX300). Bought if from the same dealer that sold it new. They showed me the service records of the one and only owner (who was fanatical about taking it in every three months for service), and it only had 100K miles on it.

I have had issues with IAC valves in other vehicals I have owned, and now that the weather has gotten colder, I think I have an issue with IACV in this car. When I start it, and for about 5 miles of driving, the idle speed (in gear or out of gear) is about 1200 RPM. Once warm, it goes down to about 700 (which is normal according to the factory service manuals I bought). Also, when warm, the engine goes to normal idle speed very quickly (good sign).

Two questions:

1. What is the normal idle speed when the engine is cold? I would think 1200 is a bit high.
2. If IACV is not the issue, where else might I look?

Thank you,

John O

ciao917

I used my battery powered hammer/screwdriver. Make sure you push hard against screw head before you unscrew the screw. It worked like a charm with no head stripped.

carlover

John O...I'm not one to ever claim I have any idea what 'normal' is, but in an attempt to help with your 1st question, I started my 2000 ES300 this unusually cold Georgia morning (low 30's) and noticed high/cold idle at around 1350...drove it around the block (water temp really never reached normal) and the idle dropped to around 900.

Don't know if that helps, but I'm not sure you have a problem...is it jittering when idling high? It shouldn't...but 5 mins seems a bit long, but then again I'm in Atlanta, so not sure what 'normal' temps are for you as cold weather here is not normal.

Ali SC3

iTrader: (10)

how often does the electric part of the iacv itself fail?
I went through this like a dozen times, I have the oring on there screws are good, moves very smooth.

either I get a high idle if I move the **** to the right before reassembly, or I get a low idle if I move it to the left before reassembly. its like my iacv is not moving the **** at all. has this happened to anyone else to have the motor part fail. Im thinking I need a whole new iacv now, which is a bummer.

salimshah

It seems the slug is not moving under the coil.

The coil can be bad (check continuity) or even signal (voltage) at the connector.

Salim