avmmtrx300

I'm newbie to this forum (and never posted question to any other forum before) My problem is when I start my lexus rx300, engine would not keep running unless I step on the gas pedal and once I let go of the pedal engine is dead again. Does anyone out there have an idea on what is causing this problem?
(FYI - I'm the original owner and have never replace battery before)

Thanks.

Jubane

I had the same problem also and it was due to two problems. One the battery was on its last days and the other was the spark plugs. What would happen to me is that I would turn the key to start the car and I would hear the engine turn but it would not start. I would have to turn the key again and hold the gas down to start the engine. Now and then I would have the exact problem you did that I would have to hold the gas down to keep the car on but after one or two minutes it would be ok.
Once both items were replaced I no longer had this problem. I would take the battery to be tested its free at all auto parts stores and the easiest problem to isolate. If the battery is replaced and you still have the same problem I would recommend replacing the spark plugs.
Again this is my experience, your problem could be cause by a bunch of other things but this fixed it for me.

salimshah

All modern cars/engines are controlled by sensors. The on-board computer reacts to the sensor signals and adjusts various things to run the engine.

There could be almost 100 reasons why your RX does not idle and one of the reason could be "bad battery" which makes the sensor put out wrong information. ... With the same chain of thought one of the sensors could be bad and the battery may be fine.

Salim

Lexmex

Welcome to Club Lexus.

You may also want to take a look at this thread that I stickied at the top of the forum regarding cleaning some of the sensors. I think this likely related to the IACV valve. https://www.clublexus.com/forums/sho...d.php?t=295546

Seize

Welcome to Club Lexus

avmmtrx300

trouble starting update

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Yesterday I bought a battery & charging system tester and tested the rx300 last night and battery is in good condition as well as the charging system.
Last night could not sleep 'coz it is bothering me too much that the problem could be in programming the key/ignition. Got up early this morning, tried starting the car and still same problem - car would start but would not stay idle unless I step on the gas and when I let go of the gas pedal car would just stop running. I remember when I bought a raw/uncut key on the internet for my rx300 (I lost one of the 2 original) and had it cut, this new key would start the car but would not idle unless I step on the gas pedal - same situation so I figured I tried to program the key/ignition again to see if it would work and it did. Car is now running fine and tested it and drove around for some chores and no problem at all. Note that all keys did not work, 1 or the original, valet key and the one I got on the internet. I only re-programmed the one I bought on the internet this morning and all keys are working fine and car is running good again.
Anyone has this situation before?

New question I have - should my rx300 running idle at 1000 rpm at least? When I start the car it would go to 1000 rpm then dropped down to about 700-800 rpm - is this normal or is my rx due for a tune up?

Please advise and pardon my long post this time.

Thanks.

Lexmex

As far as the rpm, mine starts up at 1500 RPM and then comes back down to just above 750 RPM, quite normal for me.

mandyfig

So, the problem was the key? Programming? Can you please elaborate?