rachel

I have a couple issues going on. My rx300 seems to not be getting gas then all of a sudden it takes off like a rocket, it runs ok once your above 50mph but below it doesnt want to run. I have been told it sounds like the air control valve is sticking thought I would see if anyone else has other suggestions. Also the AC only blows air to face mode, it does not switch to window or floor modes??? It has just over 100k. I appreciate the help

salimshah

May be time to have the RX hooked up to computer to see what the sensors are telling. Just make sure you do not disconnect the battery as it will clear out the codes. On the other hand you may like to clear out all the codes by disconnecting the battery (30 min or so) and observe a change. I would drive for a week or so before going to the dealer for further diagnosis if needed. [this period is needed to accumulate new data]

There is a air servo which directs the air. Some one did a write-up on it. I need to search for it as my servo seems to constantly hunting. My project for this weekend.

Search found this for me:
https://www.clublexus.com/forums/sho...ight=air+servo

Salim

rachel

We replaced the idle air control valve & all spark plugs. Still idling down, black smoke, lots of carbon, 3 front spak plugs were really black-whats wrong?

Lexmex

Is the black smoke constant, meaning all the time?

Black smoke is usually a indication of running rich, too much fuel, too little air...leaky/faulty injector, clogged air intake (filter, carbon buildup in intake manifold). Occasionally, though I doubt it, could be burning some oil, though usually this occurs when oil is pretty much sliced and diced, a.k.a. sheared to death, old oil.

rachel

There is a gas smell from the tail pipe, does that help? Thanks

TunedRX300

Do you have a check engine code, as Lexmex and Salim suggested, need go to Autozone and get the CEL code out. Sounds like you are running rich with the bad air fuel sensor on the front bank.

edbro

On the back of the IACV there is a small round rubber gasket. If that falls off you end up burning coolant. But, that is white smoke and very foul smelling.

rachel

It is bringing up a code for bank one oxygen sensor, but its brand new-could it be something else?

Lexmex

You mean the oxygen sensor is new?

A/F sensors (air/fuel sensors) as the oxygen sensors are called on the two banks can go on this vehicle. Do you remember the precise code that you got?

The gas smell means that it is running rich.

When you were describing in your first post about how it seems to not be getting gas and then it takes off. This is more likely related to air/fuel ratio and not enough air for the amount of fuel going in. As you accelerate, the amount of air will increase and the vehicle will do a little bit better in in the a/f ratio and you won't feel as much problem then.

However, faulty oxygen sensors can indeed cause the problem you are facing and it would need to be replaced.

TunedRX300

Air Fuel Sensor is wide band oxygen sensor, not the same as your regular oxygen sensor, as the one after the catalytic converter.
Bosch had a bad batch of A/F sensor that it mistakingly uses oxygen sensor, use Denso, which is OEM for Toyota.

toy4two

I once replaced a distributor and a car still wouldn't start. Kept telling myself, no way it could be the distributor I just put ina remanufactred one from the local auto parts store. So I took it back and got another one. Same damn problem, wouldn't fire up. So now I'm thinking it can't be the distributor I just tried 2 remanufacturered ones. So I have another club member bring over his MR2, we swap on his distributor, fires right up. So I wound up getting my money back, about a month of downtime and it was all because I didn't buy a OEM Toyota part, I'll never do that again.

rachel

code is p0171 bank one O2 sensor. we put a MAF sensor in today. Still ideling down & some black smoke/gas smell. I guess it could be the O2 sensor we replaced is bad. Any other ideas??

Lexmex

P0171- air intake (usually a loose hose), engine coolant temperature sensor, MAF sensor, malfunction with either one of the A/F sensors, injector probem, usually blocked, fuel pressure

But now that you have P0171, that may help me think things a bit. When this occurs, the vehicle's computer is saying you have a higher air/fuel ratio, now in this case it is then telling the injectors to stay open longer (more gas), but if that extra gas goes in and there is no air (since this is read as a lean condition), thenb bingo, excess gas gets in the mix and flies out the back in the form of black smoke.

Now Bank 1 is behind engine. One thing possible and not just with any scanner, but mechanics usually have a more advanced version that can see what both banks are reading. It might just be that the connection of the A/F sensor (or O2 if you want to call it that), is not clean or the sensor is getting too low of a resistance. I also keep a scanner handy but have to go over to my uncle's to check out the two banks as he has a more advanced scanner.

rachel

I was told maybe it was the MAP sensor but I guess there are 2 different types, I'm not sure which one I need. Could this fix the problem?? I will check for loose hoses etc. Jeez if I ever divorce I'm going to marry a good mechanic haha

Lexmex

You really need to see with a mechanic what the readings are on the two banks to actually know. P0171 is the most common error that exists on the RX300 and could mean several things as I mentioned in my last post.