LA4Mead

After the code was read (171, system too lean?) I cleaned MAF and IACV, using a good portion of a can of quality CRC EFI cleaner sprayed into butterfly intakes while revving; blew out a little carbony stuff till exhaust came clean, synthetic oil change, and serviced K&N engine air filter. Then I cleared the codes by disconnecting the neg battery terminal and pulled the EFI relay under the hood.

The CEL comes back on after driving an hour or two, intitially with TRAC OFF (early 2WD RX300)and upon restart CEL remains on. After clearing, it seems to come on after driving an hour or two upon moderate (1/2-2/3 throttle) acceleration (freeway onramp uphill, etc.).

I'm taking it to my neighbor Toyota dealer and asking for sparkplug replacement, oil change and read the trouble codes again. Is the dealer going to say I also need new expensive oxygen sensors?

Does anyone know the locations for each sensor?

How many O2 sensors are there?

I've done O2 sensors, etc. on other cars before, and have no problem with investing in it so it's running right. I just want to be prepared, because if it's a set of sensors I can replace myself, I'll save money on the parts as well as labor, and right now without an income I don't have extra dough laying around.

Thanks
Jay (So Cal)

Nad1370

Actually, your P1346 code is gone. Which meant you had a bad OCV regardless.

As for both cats being diagnosed bad...how come only 1 bank has the lean code?
Either way, that repair will cost you an arm and a leg at the Dealership.
As Rog sugg. Get it to a reputable Muffler shop.
Some causes of failed Cats are age, improper fuel/timing delivery, A/F sensor(s), fuel quality, etc....

code58

Jay- there are actually 2 A/F (air/fuel) ratio sensors and 1- 02 sensor (BIG difference between 'em, even though they look almost alike). the A/F sensors are on the exhaust manifolds shortly after it comes out of the engine. They are the same sensor #, front and rear. The 02 sensor is under the car, right under the drivers seat. The A/F sensors can be purchased on Amazon (OEM Denso sensors under the Denso name & part # rather than Toyota) for around $100. each which is an incredible price. You live in Ca., so you should be able to change 'em, they shouldn't be rusted solid like the rust belt states would be. Make SURE you actually need them before you buy 'em though, that's a lot of money and work, if you don't really need 'em.

omanely

Hello again every one. Its been a couple of weeks since I checked in, been running around with the dealerships bull. So this is where I am. Still having multiple miss fires, bank 1 only. the dealer said everything I did was perfect. Tmb , O2, spark plugs, mass air, ocv, coils. I'm missing something. Bottom line they came back with bad cats. changed the cat coming from the block and the one before the resonator. still nothing has changed. The dealer is claiming that the resonator is also clogged. To prove to them that it has nothing to do with it i disconnected the exhaust @ the flange where the y meets the cat before the resonator. same thing. nothing has changed. yes the o2 is not reading flow. but when its all connected the first cat off the block gets cherry red( to much fuel being dumbed). what can it be? I have a feeling these guys r messing with me....

omanely

Hello again every one. Its been a couple of weeks since I checked in, been running around with the dealerships bull. So this is where I am. Still having multiple miss fires, bank 1 only. the dealer said everything I did was perfect. Tmb , O2, spark plugs, mass air, ocv, coils. I'm missing something. Bottom line they came back with bad cats. changed the cat coming from the block and the one before the resonator. still nothing has changed. The dealer is claiming that the resonator is also clogged. To prove to them that it has nothing to do with it i disconnected the exhaust @ the flange where the y meets the cat before the resonator. same thing. nothing has changed. yes the o2 is not reading flow. but when its all connected the first cat off the block gets cherry red( to much fuel being dumbed). what can it be? I have a feeling these guys r messing with me....

code58

I doubt that they are actually "messing" with you, although anything IS possible, The cars are VERY, VERY complicated these days (and you ought to see the NEW ones) and there are too many mechanics that bluff their way along but aren't up to the task of ACTUALLY knowing all they need to about what they're working on, even in dealerships. The 2011 Camry I bought my wife a couple months ago makes the '02 that we had seem like kindergarten compared to it. That's a pretty basic 4 cyl. and it is more like a space shuttle as far as complexity. (I mean the whole car) To compound the problem, no matter how many times they guess wrong (at $100.+ an hour), they're always sure you needed that part anyway, (they're dead sure not gonna take it off and not charge you for it), but now there is SOMETHING ELSE that's gone bad! It's most of the time not called "mess'in", it's called "incompetence" and unfortunately, it's not at all rare!