Don't assume Costco premium really equals premium. You get what you pay for. It's probably akin to regular.

Costco is a top tier fuel retailer

http://www.costco.com/kirkland-signature-gasoline.html

new 2016 RX350. loud noise when accelerating slowly. The noise is at very low frequency which make me feel headache. when breaking, it occasionally vibrating. Will go back to dealer to check AGAIN this weekend. This model is just suck!

Its on Costco's website so it must be true.

I agree - big mistake going 2016. Ours is a fwd and has the loud noise when starting from a stop like the others. Whats more is with the fwd, when I accelerate, the car bounces back and fourth like driving on a sponge. Not a fan. Wish we got a last gen certified. ughhhhh......

Question for awd owners - does your car bounce when accelerating from a stop? Its almost like hydraulics...

you guys should make a youtube video about the noise and vibration. get the word out there and lexus will listen. Like the 2015 honda CRV vibration.

Mine rx 350 is AWD. I also feel some bounce when accelerating from a standing stop. It mostly happens when the speed reaches about 40 - 50 mph and around 2000 to 2500 RPM. I have to either accelerate very gently or much harder to get it smooth. I think the transmission is not at the optimal gear when I do the moderate acceleration. I am going to hit 5k miles in a week or two and I will ask the dealer to check this issue. If you get any feedback from your dealer please post.

Washington state where Costco is based has very strict laws about gas octane and other claims. Do you really think a 68 billion $ corporation is going to play those kind games? My wife uses their premium in her turbocharged Mercedes and it runs great.

All corporations play games regardless of size. Just think of VW as an easy example. Not saying I think Costco is lying though.

Equating a computer algorithm buried in hundreds of pages of ECU code to falsifying octane and or detergent additives claims, which are very easy to verify, is a bit of a stretch. This is why I said "those kind of games" I do agree with you that corporations sometimes play games, but this would be a really dumb one to try and pull off, since it is so easily tested. I don't think Costco is lying either. If anyone has proof they are, the Washington State Attorney Generals office would love to talk to you.

Stop the witch hunt guys. Gas is gas except for additives. Costco has the same source for gas as many other stations including Chevron. Costco contracts with different suppliers in different areas and all Ethanol is now blended at the refiner. Because of the cost to transport fuel, major brands swap with other brands in some geographic regions. Unless you live in a region with a brand that also has a nearby refinery, you could be buying the same fuel at several stations except for brand specific additives such as Techron (Chevron).

Considering a 2016 rx350 awd. Can users clarify if this is only found in the fwd models or in the awd models? Dealers says this is a fwd problem. I'm afraid to commit to this purchase as the dealer says thousands of satisfied owners and they may hide behind "it's designed that way, so not a defect" excuse. Seems like a mistake to buy it if there is no resolution as to what is causing this problem. Is it a transmission noise? Does it appear in only certain gears? Is it rpm related? Is it exhaust related? Please clarify.

I believe this Aisin manufactured 8-speed transmission is not as smooth operating as it could be. The droning, early upshifting (resulting in next gear sluggishness) and overall smooth shifting from a standing stop, can possibly be improved with a software update. The 2016 Honda Pilot's ZF 9-speed transmission was greatly improved after their transmissions received a software update (according to Pilot forum member testimonials). I'm hoping Lexus will consider this for us as well.


https://cimg2.ibsrv.net/gimg/www.clu...fde29a31c7.jpg

I don't think it's just this 8 speed transmission, I think all of these high gear transmissions are proving to be difficult for manufacturers to program well. My Grand Cherokee had awful 8-speed transmission issues that required several software updates to feel anywhere near smooth, and only felt decent in non-eco mode. The Cherokee has a 9-speed that is getting a lot of similar complains of not shifting well, constant "gear seeking" and other similar complaints.

From all of things I'm seeing from every manufacturer, it seems like these 8 and 9 speed transmissions are trickier to deal with than expected.

Why not go back to 6speed trans? Maybe only 1mpg hit