justin4797

My first post!

Hi I'm Justin. I'm looking to fix a Lexus that keeps on tickin!
(1999 RX300 FWD 250,000+ miles)

Please tell me if the following recommendations, in order, would be a waste of money:

clean the MAF sensor (cheapest, easiest)
replace temperature sensor
replace MAF sensor
replace O2 sensor
replace solenoid D
replace knock harnessses
replace knock sensors
replace entire transmission (most expensive)

I turn the key and the starter sprints like mad sounding like someone just yelled "Clear!" and revived it.
I press the gas or the tachometer goes to zero and I start all over.

And whenever I use the radio, A/C or heat, the computer screen dims or flickers.
I assume it doesn't have enough power, so I rev the engine for extra juice.

I've spent a year in Limp Mode with no O/D when I do get out on the road.

So I will definitely buy 2 things:
I'll buy a driver-side O2 sensor to hopefully remedy above problems
I'll buy a new thermostat so the engine warms quicker

I wrote error codes in the fall 2012,
but need to plug-in at auto parts store again

"Shift Solenoid D"

I clearly remember that code, which could be causing Limp Mode
I've read and heard this code is rare.
I drove it with a mechanic as it shifted into gears and the computer showed it is telling the car to engage 4th gear but stays in 3rd.
(CEL is on, but I don't drive with "O/D Off" lit)
I've read if the CEL is on, RX300's will automatically enter Limp Mode.

Shifting gears takes finesse

Instead of redlining through shifts, I rev slowly and baby my Lexus from 1 to 2 to 3. You can barely notice.
But if I tried to sell this car, any test driver pressing the gas pedal would feel each sudden shift.

Decelerating hurts

The car drives smoothly, but when you see a red light, brace yourself.
The transmission will feel like there's a little slip or a bump every time you slow down to a stop.

Harsh engage. Rough idle.

Shifting to any gear, including Reverse, takes nearly two seconds. And it is slightly harsh.
And while you're waiting for two seconds the tachometer may simply fall down to zero.
RPM's are low at idle and I must hold both pedals at stop lights. To idle smoothly and not lose power.

Mechanic says transmission fluid is sludge. Smells foul. Do not flush.

I've wanted to replace the transmission for a full year, but it's still driving.
So I'd like to try some moderately priced repairs first.

Thanks everyone!
Justin

gazi001

You got lot of issues. Start one by one. You could do IACV cleaning for smooth engine runing and reset the codes check what else come later.

salimshah

Welcome.

Just take care of the CEL codes.

Salim

hypervish

+1, definitely clean the IACV.

BTW OP: Is this the original transmission at 250k+ miles?

Lexmex

Welcome to the Club

I'll second Salim, handle the CEL codes first.

However, what is the top main issue that is bugging you about the RX right now?

justin4797

The top issue is the transmission ($1200-1500 rebuilt plus labor of $500)

I have an offer for $6000 for it.


I drive it in 3rd gear no problem all the time, but I can't sell it in this condition.

A flush might lock it up completely, or it might fix it. Not worth risk at this point.
If it starts going into 4th gear, I'm ecstatic.

Clean the IACV
Clean the MAF sensor
Replace the O2 sensor

Then find a way to get 4th gear back.

salimshah

Do not flush.

IACV and MAF (use the right cleaner) 1-2hr DIY

Reset CEL
Read cel on onset.
Fix cel based on importance, time, money etc.

I and many others would walk away from vehicle with cel ans no Overdrive. No overdrive can be a consequence of CEL.

Salim

carguy07

Take the $6k and run.

kalali

I agree. But in the next statement you say you can't sell it in this condition.
I'm not sure what you're asking here.....Just drive it until it dies...

maxSteel

Why not drop the transmission pan, drain the transaxle, clean out or replace the filter, change as much of the fluid as possible. No idea if the shift solenoid could be affected by the sludge.

Take out the starter and see what is wrong with it

Clear the codes, see what comes up. It's not clear from your post why you need any of the other stuff you listed.

justin4797

I joined ClubLexus because I've read great responses to this specific problem over the past year.

I've easily read over 100 RX300 transmission trouble/overdrive/limpmode threads on different sites.
I just like the consistently great answers you guys give here.
I joined.

(but carguy07, I can't sell anyone my RX until I fix it up. And I don't want to offer "as-is" to Craigslist buyers wanting to test-drive it and negotiating offers. I can either get it working great or take a big loss and wonder "what-if" as someone says they'll take it, problems-and-all, for only $3K. Ouch.)

Salim, thanks for your advice.
I can change oil, tires, brakes and windshield washer fluid.
After seeing Youtube videos I feel I could replace an alternator and a starter.
Now you know how little I know, what do you think of these two scenarios:

1. Should I go with a nat'l chain or a local shop and negotiate a price for cleaning IACV and MAF (how much do I aim to pay, $100?)
2. Error codes indicated Driver's Side front O2 needs replaced, so after buying my own (Part Num 234_9009 the full unit), should I ask for a quote on labor for the O2 and have them throw-in two cleanings or is that too much work? I've never negotiated labor on auto repairs, so I don't want to insult a mechanic.

I'm stuck here, guys.

I do appreciate the help, please keep the recommendations coming: I'd love to come to a concensus and give details.

justin4797

My brother plugged my RX300 into his computer and it talked to an app on his smartphone (very cool)

He took out 2 screws, showed me an MAF sensor (looked clean), reinstalled it, car started with no more pushing the gas pedal!

Wonderful!

Now there were a bunch of codes and of course he deleted them from his phone, but I do remember one was the MAF error and another was an IACV error.

+Started car
+Turned CEL off
+Cleared codes

Started car again, no codes!

Drove down the road, tried to get into 4th gear between 50-60mph and CEL lit up again.

Drove home, parked car, new codes appeared:

P0125 - Powertrain
Insufficient Coolant Temperature for Closed Loop Fuel Control

P0765 - Powertrain
Shift Solenoid "B" (is this really Solenoid D? I think his phone app is mistaken)

P1155 - Powertrain
--Lexus-- Air/Fuel Sensor Heater Circuit (Bank 2 Sensor 1)

My wife drove it throughout the day today and only needed to press the gas pedal for one of the many starts: it's performing better when starting-up and idling is near 900 rpms!

My guesses:
P0125 - REPLACE THERMOSTAT
P0765 - REPLACE SOLENOID B or D
P1155 - REPLACE O2 SENSOR (I've read Denso 2349009 in most threads, correct?)

Thanks for contributing thus far, everyone. I look forward to more of your responses. Have a great week!

salimshah

If your vehicle fails to idle at start, check out he discussion on IACV.

One thing at a time.

Salim

carguy07

P0125 will go away when you replace the A/F sensor

lexus114

I cant believe you drove around a whole year with no fourth gear.