manvan

2000 awd rx300 145,000 miles

Ok here it goes.........In last two months I have replaced the O2 sensor that is right at the front of the motor when looking from the front of the car, I have replaced the O2 sensor behind the final catalytic converter, and I have also replaced all three cats with universal cats from a generic muffler shop. Initially CEL came on...2 days later it became sluggish and threw the lean/rich codes. That is when I replaced the O2 sensors, after that I replaced the cats one by one.

Car ran fine for 1500 miles.

Yesterday I was driving and the car became sluggish while going up a hill on the freeway(55-65 mph); I tried to accelerate harder, but a weird noise came from the engine compartment. To imagine the noise just rapidly scratch your fingernails on your laptop(underneath the keyboard....next to mousepad area or on a laminate counter top.) This noise only occurs when the car is given gas to try to accelerate through the sluggishness, it does not help. I have stopped doing it because I don't want to hurt anything.

The car is not spitting any codes since the 420 cat codes were erased. I have driven the car 75 miles since the car started acting funny.

The oil appears fine; but has not been changed for 5000 miles( I know...idiot right) I traditionally change it every 3000-3500 miles. color is normal/levels are perfect.
Trans fluid has not been changed since I have owned it(2 years/24,000 miles)
fluid is perfectly red, but the level seemed a little high earlier....will check it cold tomorrow.

Just cleaned MAF sensor( actually just used an electrical wipe on the match looking thing) don't know if I should clean the innards of the MAF.


Almost forgot; about a month ago there was a rattling when I started my car in the morning( sounded like a loose shield on a cat or something...rattled occaisionially for a week or so, but hasn't been heard for a while.) Since then it takes a 1/2 mile to a mile to shift correctly. It shifts late on all gears.....but after it warms up it ran perfectly until yesterday.

I know this is a lot, but I just figured you guys/gals could help me try to solve this issue.

Thanks in advance; and I will look forward to reading your responses.

Ray

thomas1

This is the proper cleaning for the MAF

http://www.lexusownersclub.co.uk/kno...v2&id=152&c=11

ripratama

Could be the catalytic converters. I suffered from the same symptoms also: scratching/shrieking/rattling noise when throttling up at high speed but not when idle, sluggish acceleration. Replaced the 2 cats (one upfront just after the engine and another under the rear seats section) and problems solved.

Lexmex

I'd first disconnect and reconnect the battery cables off to reset the system.

So, from my understanding when you are not on a hill, you don't have this issue?

When I would go up a hill in Mexico City I would sometimes get similar noise (that's when my vehicle was original and not modified), but often when I was lower on gas, like under a 1/4 tank.

I'd also start up the vehicle and listen for any odd noise coming from the transmission area and especially the juncture between the engine and the transmission (which is on the front, driver's side).

I always mention it might be useful for two people (one driving, the other watching) to see if they can pinpoint any noise as the vehicle is being driven slowly, since the observer can see/hear things not visible when the vehicle is just in idle.

I take it you do have an OBD2 scanner? Have you shown any pending codes (codes that are in thy system when you can, but not enough to trigger a check engine light).

manvan

Thanks for responding guys...every little post may be the one that solves it.

I just cleaned the MAF and it did not solve the problem, but probably needed to be done anyways.

LexMex; the problem is not only on hills, but much harder to avoid. When I just drove the car around the block it happened every time I accelerated with any kind of force.
Per your question, the only code pending was a 420 cat code. I am very surprised the ecu has not spit another code yet.....surely it knows it is running like poop!

Also, I disconnected the neg battery cable for 5-10 mins....do I need to disconnect the positive too?

To sum it up; the car will drive somewhat normal on a flat road if you do not have the need to accelerate quickly/normally as you would usually do if you pulled out on a highway. The problem really shows up when accelerating. Again the noise is a weird scratching sound that I described earlier.


Thanks so much guys/gals


Ray

Lexmex

I'd disconnect positive, too.

Just a test, have you tried in Park, and then tried the accelerator to see if you get the same sound?

manvan

LexMex,
I just revved the engine in park and it sounded perfect.
Apparently the problem only occurs while in gear/moving.
It didn't make the noise in neutral either while I was coasting down a hill.

Thanks again..

Ray

praxis

while driving sunday i heard a terrible sound under the hood. i slowed the car down, pulled over and looked under the hood, nothing... everything seemed ok. got back up to speed, again that horrible sound, it was like metal on metal it seemed. you can imagine my mind was racing about what the hell was wrong. again, as soon as i slowed down and pulled over... no sound, i revved the engine, no warning lights nothing. the gears shifting felt fine, the engine was fine at a stop.. i thought "what the hell?"

turns out, had the oil changed the day before. the shop put the three plastic protective cowl pieces back under the front of the vehicle...(you all know the oil filter change procedure from hell) but neglected to put the bolts back on... the front piece came down and was getting caught in the wind and scraping the road at a certain speed then going back up when i stopped... it was a gawd awful noise that sounded like dollar signs to me... turned out to be somthing simple and totally not what it sounded like. (thank goodness)

sometimes its the simplest things, (and sometimes not) and sometimes it turns out to be the thing we least expect. i hope your problem turns out to be something cheap and easy too...

sorry for the hyjack.. just wanted to interject the idea to look at nonconventional causes


*edit to say best hopes for a speedy resolution too!

Lexmex

Ray,

Another idea I have is that if you could get it over to a garage that has a lift. Namely one that has a lift with arms that can be placed underneath the vehicle instead of a lift you drive upon. Note the one here at my uncle's shop back in Mexico City (this is the kind).

One would then be able to start up the vehicle and put it in Drive and then accelerate and see where the issue lies.

manvan

Ok guys.........just got home from muffler shop....replaced two mufflers and pipe.....there was all kinds of crap from my cats in there. Car is running great again; hopefully she will give me many more miles!

Thanks for the help.

Ray

lexus114

I wonder what the heck that was from?? and will it re-occur? But any way,I`m glad you found the problem.

code58

Lexus- He should keep the cats in the house where they belong, keep 'em away from the mufflers and it won't happen again. You know how cats are, can't keep 'em away from your mufflers. I have the same problem!

lexus114

Hahahahaha!!

praxis

wink wink

glad you found the problem and it wasnt too bad... my long winded dufus story above wasnt completly a lost cause ha? lol...

blueridge

Hey! It can happen!!!