Lexmex

An overhead view of the piece. What you want to do is disconnect the hose on both sides of this piece and then clean it with some cleaner (carb cleaner, engine degreaser) and then wash the piece out with water.

What cleaning that IACV valve and this piece should take care of is some low idle issues that sometimes occur with these vehicles.

Lexmex

This is what you have to do with that piece, remove it and then spray as shown and the spray should come out both of the lateral sides. Then clean out with water and blow air into it.

Lexmex

Now this is the air assist hose after I have sprayed cleaner into the IACV hole at the top and you will note the cleaner coming out of the air assist hose.

archangels

I have a question lexus recomends premium unleaded fuel of 91octane or greater, i was looking online for a descent family car rx 300, then when i came to ask the owner on who's rx300 i was interested i asked him a question, i asked him does he always use premium unleaded of 91 octane or greater, he said he mostly used 87 octane fuel with no problems.... so now i backed out and have a big question in my head if lexus recomends 91 premium fuel what will happen if you used 87 octane fuel instead? can you harm anything on your vehicle? can any expert in this forum please advise on what could go wrong or bad and etc if you went to 87 fuel octane? i know putting 91 premium fuel makes car smoother and more responsive and lessknocks and pings but anything other then that that can cause maintaince issues and etc? thanks

Lexmex

Even though my gas is 92 octane here, I would take an 87 octane American gas any day, just because if the quality issues I have been having with Mexican gas.

Realistically, you aren't going to see too much difference, some people do notice some pings here and there, but as far as something hurting your vehicle, nah.

TampRX300

now, does P1135 equals bad O2 sensor?

Lexmex

It is an air/fuel sensor behind the engine.

TampRX300

so the A/F is the one on Bank 1 and the 02 sensor is in front of the engine Bank 2?...

lexus114

2 a/f sensors,one on one bank (exhaust header),the other on the other exhaust header.1 o2(oxygen sensor)after the catyletic converter.

lexus114

In re;to archangels question,suposidly the a/f sensors last longer on premium fuel.

rx300s415

Ok, I just took out the MAF sensor today and realized...there wasn't even a red diode. It was so dirty it just looked black (on one whole entire side). I ran over to the local auto part store and grabbed a can of "MAF Sensor Cleaner," it's some solvent-looking spray made from CRC. I came home and gave both sides about 10-15 sprays of the cleaner. Forgot to spray the two thread-looking things that you seen when you turn the sensor upside down. I've been getting 13mpg in the city, so hopefully I'll start seeing improvements. Thanks Lex for the list of things to check!

BTW, I'm running a K&N air filter....maybe that's why the sensor was all dirty and oily.

lexus114

Another reason the a/f sensors dont last too long, is due to their much higher operating temp.than the o2 sensor.Average life of an a/f sensor is around 60,000 miles.

Lexmex

That stuff from CRC is excellent, perhaps the best product on the market, wish they would sell it here for my Uncle's sake.

6.0PSD

Well just finished my first full tank of fuel since I bought the 99 RX. With 83,500 miles the computer reading is about 12.8 average. I got about 208 miles on full tank when fuel light came on. Finally deciced to get to a fuel station to top it off and I had 221 miles on the full tank.

I should see better than this on mostly city/town driving. It was driven mostly 35 mph or less and very little highway.

Looks like I have something else to do soon and it's all on this thread. Hope it will help with fuel economy.

I have noticed that the sensor on the front manifold looks new, so it was changed not too long ago. I have to find where the other sensors are to see what they look like.

carguy07

"I have noticed that the sensor on the front manifold looks new, so it was changed not too long ago."

Question is was it replaced with the correct one. Some of the aftermarket parts will not do the job correctly. Is it an A/F sensor or O2 sensor?