zozoramelu

Hi Guys,

Yesterday when driving back home I accelerated my engine a bit too hard to jump on the third lane. The engine/transmission responded fine the first few seconds but after that it started to feel like it was pulling and letting go, pulling and letting go in sequence. This was not the first time it did that, I remember another time when it did the same in the same situation, accelerating hard all of a sudden. At first I thought my tires were slipping because it was raining... After 3-4 seconds of doing this yoyo, the check engine showed up and a message saying that the AWD was disabled because of a problem and the car was in FWD only. I could not accelerate, it was jerking off. I got scared and pulled over. Stopped the engine. When started it again, all was ok. I am going to go get the CEL codes now, see what I find...
Oil changed a week ago, I usually drive in ECO mode.
Never changed the transmission oil, car has 150k on it. New engine at 95k installed.
What are your takes on this?
Any ideas?

zozoramelu

Checked the codes, random multiple cylinder misfires...

Solara350

Don't worry be happy!
Your transmission is fine, but your 2.0 Turbo Engine having a problem and NSTHA stated on the website for all Lexus 2.0T NX,GS,RC,IS years 2015-2020, the NX 2015-2017 is on the list of Service Bulletin Board from NSTHA, the problem is...
"Air Fuel Ratio Imbalance and Cylinders misfire DTC" for more info here on the Government website https://static.nhtsa.gov/odi/tsbs/20...90467-9999.pdf
YOu said a new engine was installed at 95k, why ? what's wrong with the other engine? download the pdf files on that link I gave you and show them to the dealership, I don't know if they still cover but they will check your VIN# if your car is affected they'll do something to work it out.
They probably gonna replace some Head Gaskets Cylinders, Head sub-assy, and seal valve stem, valve exhaust I think, but since you provided the engine codes and this came up when I look it up for you, double check with Lexus USA or Canada.

I just bought a used Lexus NX too, before I got this one I went through 3 of them, the 2015,2016 NX I saw an engine oil leak near the water pump, not sure if the water pump leaked or not, they look wet around the head gasket, did not check under the car I ran away even though it is $5-6k cheaper, I don't wanna be like the BMW or Mercedes issues again, fix isn't a problem but damn Waste of my time and time is money, 80% of mechanics in the shop are an A-hole, find a good honest Lexus Dealership and see if they'll help you, good luck sir.

PS: 2 years ago after I switched from IS350 to RC350, my RC350 was doing YoYo LOL on freeway at 60mph 100km/h, but it's not this my RC350 is 3.5L engine non turbo it's N/A engine, I knew it was dirty fuel injectors or bad gas from Esso Canada, I did not stop or frighten like you LOL I changed to Sport+ mode and did an Italian-Tune Rev-up the engine like crazy, everyone on freeway moved away from my car LOL, and the Yoyo stopped after 2 minutes, and never happened again, I only trust Toyota Lexus 6cyl ! i bought this Lexus NX for my wife/son, if I drive I drive 6-8 cyl from Toyota Lexus, they never died.

zozoramelu

Thanks for your reply.
i found that same pdf in my research online last night.
The old engine had to be replaced due to piston slap issue, here is the link to the full story:
https://www.clublexus.com/forums/nx-...l#post11529570

I remember they told me the valves and the assembly wasn't changed because it was ok.

Well, the car is out of the powertrain warranty now.
But, I will try my luck at the dealer where they changed my engine, maybe they will consider doing it since the engine is newer...

I was wondering if I can use one of those magic bottles out there, valve cleaners, something like this:

...or this:

What do you guys think?

miop4000

The 2015 NX 209t had 2 major engine issues:

1. Rear main transmission seal deforms and leaks.

2.Hesitation issues at high turbo rpms

TSB issued 2017

Turbo wastegate pump replacement with wider diameter hosing fixes the problem. Some shops only replaced the wastegate and not the associated hosing. This sent the car into limp mode.

zozoramelu

Hello, can you please PM me with a bit more details?

Thanks

miop4000

See attached.

zozoramelu

Ok, thanks a lot, but... this is different from what you posted in #5 (Turbo wastegate pump replacement with wider diameter hosing fixes the problem).
Which one is it?

zozoramelu

Well, hello again, it appears that I was sent on a completely wrong path with the rocking forth and back of the engine at high rev and the TSB posted. I followed the TSB and replaced the solenoid and the hose with a thicker one, and guess what? The issue was still there...
Then I took another look at the whole issue with CEL codes and all (and lots of internet researching for symptoms). Back to square 1. And then I had an idea, the C\EL codes were screaming at me (cyl1 misfire & multiple cyl random misfire) ever since day one. I went on a hunch and changed the spark plugs, but not before I switched cyl1 coil to cyl2 (same issue/codes). To continue on my hunch, I used the old hose and solenoid. Disconnected the battery for 30 mins while changing the spark plugs. When connected back the battery and started the engine, it had a short hesitation and then it was purring like a kitten. The test on the highway went very good, no engine rocking, no limp mode, no more misfires. Just for the heck of it, look at those old spark plugs. The second picture first one on the right was cylinder1, you can see the distance between the electrodes is a little wider than all the other 3. Problem solved.