Typically after slowing down to make a 90 degree rolling turn onto another street my RX will feel like it's hesitating just a bit before it takes the gas and starts to accellerate.

It's like when I'm doing under 5 mph and I slowly push on the gas pedel, I get the sensation I am pushing the pedel but I'm still coasting, then the RX takes the gas, does a slight lurch to speed up and then runs smoothly.

It's like moving your mouse and the pointer doesn't move, then all of a sudden the pointer jumps to where it should be and works fine.

It's not all the time. Just some times.

Any ideas?

Thanks.

 

Try getting some fuel injector cleaner (as a first step, I like Techron). Could also be time for a tune up - when is the last time you had plugs, air filter, etc?

Last idea on what it might be... some Lexus drivers feel hesitation because of the drive-by-wire or adaptive/learning systems in many Lexus... not sure if the RX has it, but sometimes when I feel hesitation in my GS I will reset the ECU by pulling the battery cable for a while or yanking the ECU fuse. May be all in my head, but it seems to work.

 

I added Techron earlier today and the air filter was changed less than a month ago.

Last tuneup was quite awhile ago. I guess I could throw in some plugs and maybe do distributor caps and rotors.

But the car runs fine, smooth, good pickup, etc.

 

I would suggest two things:

1. Fuel filter related. How old is your fuel filter?

2. Throttle cable related. When I bought my used '99 RX300, the cable was so loose, it was difficult to drive smoothly.

Good luck

JB

 

Thanks JB,

I looked at the cable before, actually there appeard to be 2 cables, one from the gas pedel and one from a black box on the right side. Maybe this box helps idle, etc.

But the cables appeard to be snug, no slack, however I didn't have someone push the pedel slowly while I watched the action.

Thanks for the suggestions.

 

One cable is from the gas pedal and the other (black box -passenger side) is from the cruise control. The outside rigid plastic cover will always be snug... the wire inside the rigid cover is what has to be snug.

The Lexus I drive ('99 RX300) has no "drive-by-wire" capabilities, only old fashioned wire between the gas pedal and the throttle body.

Also, contrary to the other car I drive ('99 G20t), the gas filter of the Lexus is inside the fuel pump inside the gas tank!


Hope it helps

JB

 

Hesitation when opening the throttle -

Probably not the filter, that would come into play at high power (fast speeds or hard acceleration).
Probably not the plugs, a rough idle or poor acceleration would typically result.
Probably not the fuel injectors, but could be. Typically dirty injectors can be felt at moderate or hard acceleration. (Use the Techron, it's always a good idea.)
No distributor cap or rotor on the 300 to change.


Questions:

1) does this happen only when making a turn (left or right)? How about from a slow roll or dead stop?

2) how does the engine respond without load (in neutral)? Does the engine rev ok?

3) how long has this been going on? How many miles on the vehicle?

 

I notice it more in a slow turn when I drive, but when my wife drives it, as the passenger I can feel it because I keep thinking my wife is an unsmooth driver. In other words, it's like she's always pushing the pedel to fast from a stop or slow start. It's like a short term Jack Rabbit Start.

I haven't tried the Rev in neutral. I will and let you know. This has been going on for a long time. Ever since I can recall.

We have about 100,000 miles on the car now.

Something that may not be related, is that every morning I start the RX for her to let it warm up. Some mornings when I start it, it just takes off to a smooth fast idle. Some mornings it likes to start and then act like it wants to die, then catches it'self in the stall and recovers to a smooth fast idle.

Thanks.

 

" notice it more in a slow turn when I drive, but when my wife drives it, as the passenger I can feel it because I keep thinking my wife is an unsmooth driver. In other words, it's like she's always pushing the pedel to fast from a stop or slow start. It's like a short term Jack Rabbit Start."


This is exactly why I checked the throttle cable a few days after we bought the car. I noticed a bit of a delay when I lightly pressed the gas pedal and my wife was "not smooth" at all. I took so much slack off the throttle cable that now, it has only a few threads that hold the nuts in the bracket.

Check how slack the wire is between the 1/4 round thing that is by the throttle body and the bracket that holds it.

If you are not sure about what I am talking about, I will send you a picture tonight, when I am back from work.

JB

 

OK,

I went out with two 12mm wrenches, loosend the nuts and realized there was slack in that cable and actuator. The cable pulled the actuator before it engaged the throttle shaft.

I tweaked it and the wife and I are headed out to get some dinner. She will see if it's better.

Thanks, I'll let you know.

 

Well, adjusting the linkage definately helped the problem.

I still had some hesitation in the same corner I seem to always feel it. Maybe it was because I had about 400 lbs of goods in the back end and that just amplified the feeling. But it wasn't as noticeable as before, when I felt I was pressing the pedel and not accellerating.

I think I am going to adjust it with the engine running and keep adjusting it until the engine just starts to increase in revs, then back off a little. That way I'll know I am right on. Although, I am really close now. I probably took 1/4" slack out.

 

I have a '00 RX300 and I have a similar issue with mine. When I come to a rolliing stop and then hit the gas to go it seems to hesitate. It is more noticable when taking very slow corners and then hitting the gas to go. When I brought it into the dealer they said it's not the engine or anything else that's "wrong" it's the electronic transmission of the 99-00 models that make it feel like a hesitation. The tech described it as the computer thinking that I was going to stop, but didn't and then when the gas is applied the transmission takes a second to respond properly. The timing of the transmission shift is what causes the feeling of a hesitation. Maybe the adjustment helps, but it may not be the root of the issue. Let us know how you make out with your adjustments. I'd like to get mine as best I can too.

JP

 

JP

I totally agree with you and would not argue with the Lexus tech. The last automatic car I bought for me was an '85 Chrysler, in '85! My wife had an '92 Nissan 240SX automatic which shifted very nicely, especially after a fluid change. When we bought the '99 RX300 last May, it was very sluggish in up and down shifting. But the throttle cables were sooo loose... it wasn't funny!

Shifting improved a lot when I tightened the cables, and things improved again when I changed the transmission fluid last week (I towed a trailer all summer). But still, we can hear/feel the transmission working hard deciding which gear to go when, for example, we slow down to turn left in traffic: hit the gas while slowing down to a crawl is sometimes not safe because of the delay...

You can always check your transmission fluid: if it is not bright burgundy red (rather brownish) than have it flushed with only Toyota Type IV.

In any cases, you have to learn to live with this "quirkiness" or get an other car. There is just so much that we can do to improve it, I do not think that the automatic transmission of the early RX300 will ever be perfect.

Good luck

JB

 

J.B.

Glad to hear that you've had some success in making it better. I've learned to feather the gas in those circumstances to make it smooth and not jerk the car once the transmission shifts. I'm going to try the adjustments and fluid change to improve things a bit and live with the results. It's a small nuisance, but I still call this the best car I've ever owned. I'll post back my results.

Thanks again,

JP

 

has anyone fixed this problem yet?