biggywilly

Hey everyone well lately my 2000 RX300 of 160,000 miles hasn't been running the best and have no clue what it is, its running very lean I smell it non stop, it has some sort of hickup like it wont accelerate smoothly. I also have 2 engine codes and they are for one oxygen sensor and the catalytic converter, but also does anyone know where the idle valve is locate? If anyone has any idea where to start looking let me know

noku

If you can smell it, I suggest looking for a leak somewhere in your exhaust before the cat. Fix the leak first then see if the codes persist. Search for Idle Control Valve or ICT, I believe there are numerous posts and pics for it.

noku

Excellent post here for IACV https://www.clublexus.com/forums/rx-...-write-up.html Not ICT as mentioned earlier (my bad). Don't know where I got that from.

salimshah

Nit to knit-pick but I think OP meant "rich" not lean. When you run rich, the cat works overtime and you smell unburnt gas.

Start by clearing the codes, check air filter, IACV and spark plugs. Spark plugs need replacement @110k miles as long as you use OEM.

With the gas prices this high, it may be cheaper to get it repaired.

Salim

noku

At first I thought as you, about it being rich and not lean. However he did report codes and did not identify. Some codes do suggest a lean A/F sensor error which may justify his observations. Most of us would be able to distinguish a rich (gasoline) odor vice something else, so I merely gave the guy the benefit of the doubt. My bad again if I'm in error. Fortunately you chimed in to give a different solution if OP was mistaken. Maybe the OP can post the codes he was getting as that will make diagnosis more accurate and expeditious.

salimshah

Here is the logic (convoluted as it may seem)..
The sensor sends the information to the the ECU .. the fuel mixture is lean .. the ECU commands the injector to pump in more gas.

net result is engine runs rich, while the senor reports "lean".

Hope it helps.

Salim

noku

The important problem here is the OP's clause " I smell it non stop" whether being rich, lean, or otherwise all are hazardous. I take this to mean from inside of the cabin not that it cannot be from someplace else, but let's say conjecture on my part.

A properly working exhaust directs any fumes away from the vehicle and should hardly be discernible from within the passenger cabin unless of course you are in a confined or partially enclosed space. It is much more likely that any exhaust fumes noticed are originated from another vehicle(s) so an exhaust leak in your system is a real possibility.

We have all smelled oil, brake fluid, coolant, i.e. spilled on something hot in the engine compartment finding its way into the cabin. Especially on an older vehicle where engine compartment seals may not be in proper working order, the leakage into the cabin may be exponentially more. An exhaust system inspection is warranted and if not fixed could compromise your health. This could possibly be a simple matter of looking and or listening under your hood or car and not cost a cent to locate and maybe an easy fix. The exhaust's manifold, flex joint, and various gaskets also seem to be problem areas of vehicles with similar mileage. If codes are cleared, filters/plugs changed, iacv cleaned, you will still have a "non stop" smell. The smell may or may not change in composition but it will still be there. If any leak(s) are fixed or no leaks are detected then I wholeheartedly would agree with what Salim suggests.