have you looked at the throttle body? there's 2 main parts, the resistor strips/electronics part which can wear and impact plate position, and the plate/bushings etc. wouldnt hurt to look at it, at least the plate, its a 10 minute check. it shouldnt get dirty, but they do sometimes.
mine had issues at low rpm, the resistor strip wore because thats where most of my drive time was.

 

Not immediately but overtime it helps. I used Lucas oils injector cleaner one bottle for every 4000-5000 miles.

Yes, I have 2015 gx460, bought new and now it has 47000 miles. I've been using Shell 87 exclusively for the last 15000 miles and tell you the truth it runs better then no name premium gas. I keep it at 3-4000 rpm when merging into highway at an on-ramp so 30 seconds max.

 

So why aren't you using Premium fuel as recommended?

 

I've done many unscientific tests and the results tell me the premium of the premium is not worthwhile. Shell premium is 80 cents more than regular which is about 25% with current prices and I only receive about 5% better in fuel economy.

I have 7 Lexus and have used regular most of the time, except the NX200, and so far no problems at all. Note, i don't keep the vehicles pass 100k miles so the problems have NOT surfaced YET.

 

I have this exact issue with my 2018

 

That’s total BS from your dealer. If you had brought it in in the Fall or Winter, they’d say “ Oh it’s the winter gas”. Lol. I’d take it back and have them run diagnostics.

 

Bad answer, but have you tried another dealership and filled up with premium from a different station? Also when did Toyota start allowing a "gas additive" as most of their manuals state its not recommended. That service center seems to be passing the buck, since its a warranty issue rather then outright repair. If you have a fluctuating idle that`d be a cause of concern.



While I say do you, why even bother adding lucas oil injector if you are concerned about about saving 80 cents a gallon and dont keep cars past 100k? I`d just do the regular gas and forget about it any additives.

 

The additives are for cleaning, not octane booster.

Let's stay on track and hope the OP can get his issues solved.

 

whens the last time there was a tune up done?
ever checked the egr valve?
ever connect an OBD to read the throttle body position when this happens?

those 3 above seem to be the main reasons for rough idle, bouncing idle, low frequency vibrations at lower rpms.
all of those could also come from junk gas, fuel obstructions, or a host of other things.

 

vac leaks too, but i dont know that they are common on the gx

 

Hi,

Anyone know what could be the problem? At high speed, there is vibration on steering wheel on GX I recently test drove. I did few reserach and result was wheels/tires are not balanced. I have asked the dealer and he said that they run on tire balancer machine and they came out "0"

Any feedback what the problem can be?

 

If you are able I'd just skip that vehicle and try another GX or even another dealership. I had the same issue. I test drove 2 at my local dealer. The first was vibrating so bad the kids in the backseat were asking me if the car was going to make it to the next freeway exit. The second one was better but still had similar issues. I went to another dealer and the one I drove there was fine. So either the wheels/tires at the first dealer were all out of balance or they were flat spotting. I didn't want to go and figure out why the two at the first dealership were having issues so I ended up purchasing elsewhere.

 

even a square wheel can be balanced on basic machines.

 

True. But if you are purchasing a vehicle do you really want to start off with the dealership having to spend a bunch of time/effort trying to balance your tires? Unless of course if there is no other dealership around then you're stuck. At least try and test drive a different GX.

 

100% agree. I wouldnt accept the vibration.
My thought is that if you find a GX you like, and notice vibration, have the dealer take it to a place with the road force balancer and then go back to drive it again. It shouldn't be much time or effort.
The dealer saying it balances to 0 doesnt solve the problem, and the square wheel is just something to tell the dealer when they start with the 'but it is balanced' talk.