kmd221

2018 NX 300 f-sport - engine problems

*Edit Dec 2022* Do I just sell the damn thing?? Or do I try to work with Lexus?

Hey everyone. I have a 2018 Lexus NX 300 f-sport with 55,000 miles that has been in and out of the shop for the past month with engine problems.

• Aug 2021: NX 300 started experiencing rough idling (I should add- the ignition frequently had trouble turning over for a few months leading up to this). 25 miles later, the check engine came on and was flashing tons alerts: “AWD, parking brake, traction control disabled, take to dealer”. I had the car towed to my Lexus dealer. The techs couldn’t figure out what was wrong and started involving Lexus corporate. The car underwent tests for about 1.5 weeks.
  • Initial diagnosis: “Bad gasoline”… The rough idling was caused by the engine misfiring. One cylinder head was was flooding, so the car was trying to run on 3 cylinders as one was flooded due to incorrect air/fuel ratio. The techs disassembled the engine and ran more tests, still unable to figure out the issue. Eventually, the techs chalked it up to a gas issue- apparently I had contaminated gas. I kind of thought this was BS at the time (I could’ve sworn I got premium and I even had the gas station tested by the state of Maryland) but I reluctantly agreed to have them flush the tank and took the car back.
• Sept 2021: Same exact issues. Took back to dealer, they said this could be a byproduct of the fuel issue and “it could take time to clear up.” Took car back.
• Oct 2021: Same issue, same solution by Lexus. Techs decided to do a carbon clean out on the engine to flush any carbon build up just in case.
• Dec 2021: Same. Issue.

I’m pretty upset about this because I’ve loved the car otherwise, but this scares me. Especially the ignition issues over time and now this major engine problem.

Questions: I’d appreciate any thoughts/advice you guys have. Has anyone else ever experienced this?

The G Man

If the cylinders are flooded, I would have them check for leaky injectors first. Good Luck.

kmd221

Thank you! for the suggestion! I am a bit surprised if after over 2.5 weeks in the shop the dealer did not try that as a part of their test, but I'll at least know to ask that this time. I wonder if an injector would still be warrantied at 60k miles.

The G Man

That should be the 1st thing they try. If the car was in the shop for 2.5 weeks, it probably something that is not obvious. I had this happened to my wife's Audi before and the misfiring was due to a hair line fracture in the cylinder head which the dealer never found in the shop.

Torii

common sense w/no automotive background would assume if something is wildly out of balance something broke inside of it....gasoline not the issue.

miop4000

There is a whole thread on the problems with this engine.

kmd221

I must be terrible at the search feature on here because I’ve been trying to find that but can’t seem to. Any chance you have a link to it or could you let me know how to find?

RXWes

The Club Lexus search section doesn’t do a very good job finding threads.

Just go to Google and type in

ClubLexus NX300 Engine Vibration

and you will see all the threads

miop4000

https://www.clublexus.com/forums/nx-...+achilles+heel

miop4000

By the way, a dying battery in this car sends into ballistic mode.

Random codes thrown up, difficulty starting, unusual alarms and endless confused visits to the service department. The battery tends to test OK until the moment it dies.

I was told that the batteries tend to have a short lifespan with the strain of the turbo NX stop start system.

Recent visit the third battery in 5 years was replaced by a deep cycle 4wd model.

RXWes

Miop4000

Do you have the Battery warranty available to you? My 2016 just had its second battery replaced when it died. Lexus gave me 50 percent off on the replacement.

Also, You ready to trade in your current NX for a 2022 model? I wanted to purchase a RAV4 Prime earlier this year. But saw the announcement for the new NX.

With all of the issues the Prime is having. Be it reliability or availability here in Florida. I will probably just get a 250. And stay away from the Turbo 350. Hopefully I can get one without a Sunroof.

kmd221

Ugh thanks for sharing your experience! Didn’t consider the battery.

I’m hoping I can recoup $1,200 for an engine disassembly and $300 tow bill due to purchasing “bad gas”.

Didn’t think I’d ever have these issues with a Lexus!

chadhargis

I'll echo what others have said. The battery is probably the issue. I have had several cars that acted funny and a new battery fixed all the problems. I had a VW that when you floored it, all the lights on the dash would come on and it would go into limp mode. Pretty dangerous when pulling out into traffic.

My NX is a CPO and I took it in for the 50,000 mile service. I had 50,079 miles on the car when I dropped it off. The battery tested bad, but the dealer replaced it under warranty since I was only 79 miles over. I wan't having any issues, but it's nice to know it's got a fresh battery now. And thanks to the wonderful customer service at my dealership, they must have put some sort of 12v power on the wires as they changed the battery because nothing was reset. Radio presets were all there, like nothing happened.

kmd221

Bumping this thread. A cylinder is misfiring again. This is the third time I’ll be taking it to the shop in the past 2 months. Any other insight is welcome.

LexMan2003

The one thing that is not crystal clear to me is....Have you been using PREMIUM GAS in the car, or not? My 2020 calls for premium, not sure about the 2018.