Brotherbob

First and foremost thanks for your help!

Subject 2004 Lex GS300 122K miles-

I put plugs in this car 8K miles ago because it had a slight hesitation. That did not fix it.
The hesitation got worse ,kinda like a dead throttle for a second or two then BAM off we go.
It would idle low 400RPM and occasionally die , but start back up and off we'd go.

I had the CATS checked at a shop and they said go to go.

My TPS was a bit low in range so I adjusted it -idle picked up to-600-700RPM est.

I still have this dead throttle- not all the time but a bunch, Now I have a CEL and I'm off to get codes read.

When I swing the car into a turn the dead throttle gets a bunch worse! Esp a right turn- could the Fuel pump be bad?
TPS?
APS?
Loose nut behind the Black Onyx Lex?

I dont mind spending a few hundred bucks but I want to spend them wisely -please help me figure it out?

Thanks again-BOB

Debonair

Report back with them so we can offer advice.

Brotherbob

Ok I'm back but not much wiser?
The Autozone dude plugged in and said code 430 Catalyst , either the cat is plugged or you have a O2 out....and walked away.

Funny thing is while my CEL is on and my VSC and Traction control lights are my Bog or Hesitation is barely there?

Does that make sense?

Maybe they screwed up something when they blew holes in front and behind each cat to check if they were plugged?
They said they were fine and I left without a CEL on the day before?

BB

Brotherbob

OK- I think I want to replace all the O2's and see where that gets me. Can anyone verify these P/N as good to go for a 2004 Lex GS300?
1. 234-4630 upstream 4-5-6
2. 234-4048 upstream 1-2-3
3. 234-4903 downstream 4-5-6
4. 234-4626 downstream 1-2-3
???????????????
Can I just buy the cheap ones from Amazon or Ebay and make the splice with solder and heat shrink?
Any info will help!
THANKS.
BB

DMPesso

NOOOO!!! DONT! and I repeat DONT buy the cheap universal O2s, its only gonna cause MORE problems. I have heard so many horror stories about them. Your BEST option would be to find out which DENSO part number your car uses and order them from AMAZON! Denso is OEM so they will work perfect. The O2's should do the trick, if not its most likely the TPS, or it CAN be the APPS (Accellerator Pedal Position Sensor) IF your car has one. I know the 430s have one, not sure about the 300? My car wasnt dying but the pedal would lose connection with the car like how you are describing. Your problem is sounding more like a TPS but its weird that your CEL is completely unrelated because TPS wont throw a catalyst code...

Brotherbob

Ok so Denso only-check!
Amazon-Check!
Are the part numbers correct? HELP?
My GS300 has a TPS and then on the opposite side of the throttle body another sensor that looks a bunch like a TPS but is called a APS? Somehow the VSC is tied into it?
TPS is cheap , might just grab one too?
HELP!

DMPesso

the APPS i am speaking of is not on the TPS but is actually the entire gas pedal with a sensor built into it. So basically what it does is tells the ECU how hard you are pressing the gas. I am not sure what APS you are talking about but if it is cheap might as well replace it while your in there.

DMPesso

as for the part numbers I am not sure, you would have to call your local dealer and ask them which DENSO part numbers the O2 sensors are and then search for them on google or amazon and it will show you which DENSO part that number fits. Or if you want to be real sure just go to the dealer ask them to see the O2 sensors and check on the box since there is usually a Denso part number on them. Also Autozone has a pretty good system, I think if you tell them the year/make/model of your car they will tell you which part numbers fit, that might be the easiest route.

Brotherbob

OK all 4 Denso O2 sensors on the way.
I have a fuel pump,filter and sock ready to go in also.
We'll see what happens after that.....unless one of you high speed low drag Lexus dudes have another route?
BB

Brotherbob

Can anyone post a link to how to check the following parts for failure? or adjustments/cleaning/repairs?
TPS-
Throttle lever position sensor-I was calling this the APPS but its p/n 22060-46070.
MAF-
So I can rule those out?

tereck

Jajaj that must be ur main problem. Ur throttle control motor and not o2 sensors. Chill out and relax and don't buy unnecessary parts like crazy.

Brotherbob

I have no codes for anything TPS APPS related? I would like to rule them out by testing them though?

I do have codes for O2's / CATs- I had the CATS checked and they said they were good.Less than 250.00 for Denso O2s delivered to the house.

So I'm putting all 4 O2's in it , the car has 122K so I figure the FP filter is prolly full of *****. While I'm in there I'm doing a pump ,filter and sock.

I'm doing all the work myself..

It's only money we'll make more tomorrow! Hopefully I'll have everything NLT Monday labor day for a install and I'll report back what happens.

Thanks for the input.
BB

burny

Everything you need to know is in this thread. There is one post in there with PDF attached with the ranges for each part that you can test with a multimeter. By the time you read through this post, you will know how to find the problem. Read post #481 and 482 before you go to beginning. May change your entire approach to this issue.

https://www.clublexus.com/forums/per...mp-mode-5.html

burny

Did you find the issue?

Brotherbob

Update- I installed 4 Denso O2 sensors , a new fuel pump sock and filter housing- I did not replace the pump- and it seems all my problems have been solved. No lights, No hesitation.

It is idling a bit low but I imagine that's a TPS adjustment.

I think its all good.