Hello,
Your assistance will be greatly appreciated.
The Check Engine and VSC lights are lit. The car, my third RX is an 07 RX350 AWD with 300K miles.
I have replaced the gas cap, MAF sensor, all spark plugs, all coils air filter with only Denso parts and disconnected the battery to reset but to no result.
Currently, the car runs fine until I am stuck in traffic, then the engine starts sputtering and stalls if I do not keep the RPM at 1000.
Every time I have replaced an item mentioned, the Check Engine/VSC light would go out and return after a few days.

 

Did you ever hook up a scanner to retrieve trouble code(s)?

 

+1 per LeX2K, time to start diagnostics. Ignore the VSC light, it is only on because of the CEL. Time to scan for DTCs, and get the short and long term fuel trims with your shinny new scanner...

Also, you can go the route disconnecting the fuel injectors one at a time to see if the idle is affected (it should be). Lots of things to try...

 

You'd have been better off spending 50$ on a scanner, instead of throwing money at it, guessing what the problem may be...

 

Hi friend, you will need a proper scanner that can read codes and live data if you want to DIY.

Without a scanner I am sorry to say but nobody can help you unless you like to do a lot of guessing and change lots of parts. lol

 

buy a obd2 scan tool on ebay ($10). download a free obd2 reader (eg torgue lite) onto your phone you can read and delete all engine fault codes.

 

Anyone else one of those $10-20 bluetooth obd2 readers? What app do you like? I have one. Can be a bit fickle connecting sometimes. Live data seems good insofar as I can understand it. I use the Car Scanner app from carscanner.info. I like the design better than Torque Lite. The Pro version with more live data only $5 (some others want annual fees).
If I get enough feedback on favorites, I will create a summary thread..

 

Wowzer, 300K. Congratulations!! Are these mostly highway miles?
I think nothing wrong with throwing parts at it with 300K. They've been well used.
Look at Amazon lightening deals for OBD2 readers. They've always got one on sale. It can be super confusing to pick one, so many distinctions, but even a cheapo one that just reads diagnostic codes and live engine data helps a bunch.

 

torgue lite has done the job for me on a number of cars. It has the basic read error codes and delete error codes. do not know about others as torque lite is the only one i have used as it has always done the job for me