Hey guys please, help my RX300 has a mind of it's own when it comes to RPMs or something I drove all the way from North Carolina to New Jersey my RPMs reached 500.. it was a struggle to get it up to 80 once I got it to 80 and set the cruise control it would be fine but any fast accelerations drove my RPMs up and it never came back down unless I pulled the car over and reset by turning it off and turning it back on I had to do this at least six times during my trip. Quick acceleration is just non-existent I haven't had it that long fair and panic is setting in do I have a serious transmission problem send help.. so it's warm outside now so it's not because the car is cold I am letting the engine run before I pull off but it doesn't matter it could be why the engine is completely hot I run in the store restart the car and I'm back at 3 to 4 RPMs. I am afraid

 

Welcome to Club Lexus.
This is a very confusing description. Is the "check engine" light on?

 

I agree with maxsteel, as I am also confused too. lol

Wendyrh1, you saying the car maintains high rpms when coasting to a stop?

If you have a scanner I would watch the throttle angle if the RX300 supports it, just brainstorming ideas to add to others ideas.

 

Yes the check


Yes the check engine light is on, but it was only due to a gas cap error last I checked . I don't know if something has changed . as for the RPMs it's a crap shoot as to when I'm going to be at 300 RPMs going towards for at 60 MPH sometimes this happens sometimes it does not I have no idea why I have no idea why stopping the car and restarting it sometimes resets it.. If l try to accelerate too fast.... any type of fast , the RPMs shoot up to almost five. They'll drop back down but only to three and never go any lower, and then it will be stuck there and it'll be working its way between 300 and 400 sometimes 500..

 

Your RX throttle is by cable connecting the pedal to a round pulley like structure which allows air to enter. The pedal through the cable controls the amount of air that is let in by a metal plate referred to as butterfly.

With the engine not running the pedal should move the butterfly from min to maximum open. The cable should be freely moving [no kinks, frays etc] and there should be no blockage in the pedal movement from carpet or other items. There should be 1/8" of free play at the pulley/wheel side.

The pulley/wheel has another item that wraps is by a cable and that is connected to the Cruise control.

I suspect something is messing up on the crusise control side as the cruise is disabled when you turn off the engine or when you apply brake [assuming the brake switch is working]. Cruise only engages when the vehicle is moving [again a good working cruise set up is required].

My suggestion:
Un-hook the cruise side from the pulley. Test for a free play in the pedal to wheel. Check for smooth operation on the pedal-pulley. Lube sparingly if you must. Start the engine and confirm smooth operation of the gas pedal.

If your vehicle has high milage, you may be needing an air intake cleaning. Don't be tempted to do that on the engine as the junk will end up in the engine. The process can be expensive as you would be needing gaskets.

Salim

 

I take it all of these numbers are thousand RPMs? Sounds like a sticking throttle. But this shouldn't cause hesitation unless something else is going on. Start with Salim's suggestions but I think you have additional issues.

 

I'm still having difficulty understanding what's going on.

Can't tell from description if we are dealing with a slipping transmission or over-revving due to other issues.
Already great posts, just like to add more ideas for brainstorming.

Digging thru my docs I found this, 2002-2003 RX300

Throttle Position Sensor

 

There are two different type of throttle position sensors. In newer models where the throttle is electronically driven the throttle position sensor controls the throttle. In first gen RX the throttle position sensor provides kick-down indication.

Salim

 

To me this sounds like overdrive is getting locked out - could be few diff things, OCV valve, knock sensor, etc. Only way to know is to pull the codes again and see what it's throwing.

 

OP has not comeback to elaborate on what is really happening.
1) Is the engine revving up on its own?
2) Gas pedal has to be depressed hard to move at a reasonable speed with engine rpm going high to maintain say 50mph.

I guess we have to wait for an update.

Salim