Hello everyone! So I have been noticing ever since I picked up my 2017 Lexus IS350 F Sport that some days the car performs very well and shifts very smooth and drives smooth as well, and then some days it performs rough when it comes to shifting and vibration when driving. Has anyone else experienced this with their 3rd gen IS350? I’ve driven my friends 2015 IS350 and it was much smoother. I find it weird that it performs different every other day, is this normal?

 

More info would help here... Mileage? Last service? etc...

 

Current mileage is 40k and the last service was for a new wheel bearing and lost oil change was at 38k miles! Some days the car when even at operating temp vibrates a good on acceleration and I can feel it in the gas pedal! And other days it’s very smooth! Seems weird to me that there’s inconsistent performances!

 

When does it feel rough? Is it throughout the entire drive, or only when cold? I always thought my IS's transmission was a bit rougher when the car was just started up, even when it was brand-new.

In addition, I would say I'd be tempted to do an ECU reset if I were in your situation. That is, disconnect the battery for 30 minutes or more. Then, when you reconnect the battery, things should be basically back to new in terms of calibration.

One other thing... you mention vibrations, is that specifically during shifting? If all these concerns are transmission-related, maybe a transmission fluid change is a good idea. Members of this forum have reported noticeable improvement in shift smoothness after a transmission fluid change.

 

I recently did a transmission fluid change, just a simple drain and fill and the difference was very apparent. Maybe try doing the easy stuffs first to isolate the issue, change spark plugs, clean MAF sensor and throttle body. I believe the MAF sensor and TB are not standard items during service and if you use aftermarket air filter, it would not hurt to clean it more frequently.

 

Changing the transmission fluid was a thought but the car only has 40k miles! I hear from a lot of people that I shouldn’t touch it with only 40k miles. I did get the throttle body cleaned but haven’t had the MAF sensor cleaned! I think I’ll do that the next time I take it in! Do you think a spark plug(s) could be bad with only 40k miles?

 

Usually, spark plugs are due for change nearer to 60k miles, turbo 3IS 40k miles. However, as there are many causes for reduced performance, especially due to mods and aftermarket parts, it is always more prudent to start out with the easier solutions to isolate the issue. If you installed aftermarket air filters, for example, chance of bad oiling done by the mechanic. Did u run an error code diagnostic test? A cheap OBD wireless plug and iphone can read the codes and is most efficient and give peace of mind.

 

Hey there, so I did do an ECU hard reset at the dealership. I feel like it takes a while for the car to reach operating temp. The reason I believe is this may be the issue is because whenever I start my car in the morning to drive it to work, which is like a 20 minute drive, I can feel vibration in the gas pedal and when breaking the breaks feel grindy and rough! After my trip back hole from work and when I’m on my way to my gym, the car feels way smoother and the breaking is smooth as well! I feel like the car is just taking forever to get to the right temp to perform well! I don’t know what could cause that to be the case! Any suggestions would be much appreciated!

 

I have noticed on both of my ISs, that they run like crap until operating temp is reached. Power feels unsteady. Both are under 55k.

 

Do you feel like it could be that the oil isn’t getting to all the places it’s supposed to fast enough or is that just how most IS’s are? This is my first one and it’s a bit different than my previous 06 Acura TL haha

 

I did not run an OBD scanner because there are no error lights or codes! When I first got the car back in November 2020 I took it to get the windows tinted and the man that did them left the key fob near the car while working on it and it drained the batter which caused an error code to come up but the dealership reset it no problem!

 

A wheel bearing at 38k??? Maybe soneone hit a giant pot hole? Was a wheel replaced? Maybe bent arm?

 

Same. My 350 AWD FS feels/sounds like **** until it’s warmed up...transmission shifts a bit tougher, accelerates slow as hell, sounds like a diesel.

 

Yeah, a new wheel bearing! The previous owner lived in NY and probably hit a mean pothole and the wheel was replaced! From what the dealership told me, they said that whoever replaced the wheel bearing for the previous owner put a bearing for a GS on the car for some reason so I replaced it for one that goes on my IS lol. People don’t use their brains anymore I guess.

 

I always let my car run for a couple of minutes before I drive. But if the temp is anywhere between the bottom and 1/4 way to normal, it runs really weird, almost like its limiting performance. Also, in manual mode, shifting delays really bad when under normal temp. May just be what these cars do. The last IS only had 43k on it. This one has 55k. That and the weird 5th gear slip if anywhere around 1/4 or half throttle when accelerating.
There were weird quirky things with my Acura TL, that all TLs had. I guess each car will have its own weird quirks.