Tigerfever

So a month or so ago my 2015 Fsport started up with a ton of errors - check engine light, traction control, AWD, traffic sensors all turned off. It also wouldn't let the transmission out of first gear ?? Turned the car off/on and it went away. It then did this again but this time, the errors didn't disappear but the car would actually go above 20km/hr. Called Lexus dealer, their tech told us to check the gas cap and whatnot, nothing worked. We ended up removing the battery and charging it which reset the errors and they didn't come back for a few weeks. Had to wait over a month to get into my service centre and of course by the time we took it in, the lights disappeared from its time at the Costco tire centre. Lexus said they ran the codes and the engine was misfiring and they say it's from carbon buildup and it's going to require replacing cyclinder heads and exhaust valve seat. They're quoting me 10k to fix this on a car I got less than 7 years ago and we have under 100k miles on it. My mind is just blown and I want to know if other owners have run into this. I love my car but it's our only car right now (actually in the process of trying to purchase a second car which I can safely say will not be a lexus) and this is not the reliability I expected.

Lexuswiz

iTrader: (1)

I would get a second opinion at another lexus dealer/service center or an independent lexus/toyota mechanic. I have yet to hear anyone needing a new head on the 8AR-FTS and your issue with the errors sounds more like an electrical issue than a mechanical issue.

The G Man

Not sure about the Canadian version, but the US NX has port and direct injection to reduce carbon build up at the valves. Just wondering, what brand of gas do you use? Do you use at least 91 octane? Do you change your oil every year?

Gerf

Canadian version is also port/direct.

Rjngo

If the dealer is correct that you need to replace valves and cyclinder work(and etc) I wouldn’t go with the dealer for the work…$10K price quote is ridiculous!

as stated above, I would go for a 2nd opinion either a different dealership or a trusted garage shop.

Lex2000TL

Or, find engine with less miles from salvaged car.

Tigerfever

Yeah, as stated, it has port and direct injection. I use Costco gas 99% of the time and always premium. Used to get the oil changed every 4 months when I was driving a lot but definitely went well over a year between the last two as we basically stopped driving the car. Really hope I didn't cause this from the one time I went over the recommendation.

Definitely going to get a second or third opinion from a shop as we only have the one Lexus dealership in my province. The dealership said this is the second NX with this issue in the last six or so months.

The G Man

I dont think changing the oil a bit late could cause severe carbon up. unless you are using oil that do not meet Lexus specs. A faulty PCV system could also cause carbon build up at the intake valves. I had a check engine light and misfiring cause by carbon build up in one of my Audi years ago, the dealer blasted the valves with walnut shells to clean it. Another time, the dealer injected solvent into the intake valves to clean them.

kukudm

So the dealer claimed carbon buildup, did they take apart the Engine or at least the intake manifold? If they did, ask them to send show you some photos to prove it's carbon buildup, it's not that hard to zap a few pics nowadays. If they can't do it, then I'd definitely seek a second opinion/diagnosis. Misfire could be due to various different reasons, not necessarily only carbon buildup.

LexMan2003

Here's my 1 cent (adjusted for inflation):

1 - Have you changed the spark plugs per schedule?
2 - Have you checked/changed your air filter(s)?
3 - (curious) Do you use ANY kind of fuel enhancer/cleaner? I use a bottle of Techron (or BG44k) every 5k miles.
Any possibility that this would've prevented the issue(s)? Any possibility that this could be a remedy, although it might take some time to work it's way thru?
4 - If you're going for a second opinion, which I agree with everyone else on, I would NOT go to a Lexus dealership. It is quite possible that they can easily see the record/recommendation of the first dealership, and they might be inclined to agree with them just because they are 'related'.
5 - In the old days, when I was a youngin', a misfire was sometimes caused by a bad wire! Possible?

gompka

iTrader: (6)

Strange, I have not heard of any carbon issues on any Lexus cars since the non port injected is250 2.5 v6. What we did in his car was buy some chem tool carb/choke cleaner and poured it into a pump chermical sprayer. Then we sprayed it into one of the vaccum lines near the throttle body while he reved the engine a bit. Its not a super accurate way to do it, but after doing this a few times after every oil change, it dramatically improved how his car ran. I tent to agree with the others here that it sounds like an electrical problem. Have you changed your battery? In my is350 I had a similar issue where lights on dash went crazy and car ran bad, and it turned out to be a bad battery. Take it to an auto place to get tested, but quite honestly if its original just go to costco and get a replacement, don't even both testing. Then see if the car runs better.

yourddcpro

Hi Tigerfever I had the same issue with my NX200t. Lexus ended paying about 75% of the cost. I submitted a complaint with Transport Canada after Toyota Canada refused to communicate in writing to me.

I believe that this is a manufacturer defect with the 8AR-FTS engine and since this is not reported enough that Toyota/Lexus Canada is playing the numbers game and not issuing a recall on their poor build quality of this engine.

Captrob

Chevron/Techron injection cleaner 1 can per tank for a month.. Black bottle found in Walmart or online

reesesboy10

Was this solved? My mechanic is telling my to clean the egr valve.

n0v8or

You might consider a new mechanic. The variable valve timing system installed on the NX (and many other Toyota/Lexus engines) eliminates the EGR valve by allowing "overlap" between intake and exhaust valves. During the "overlap" period, both valves are open and exhaust gas can flow back to the intake internally.
In other words, there is no EGR valve to clean. Refer to this web page for more information:
https://toyota-club.net/files/faq/16...vvt_iw_eng.htm