Alldatjazz

Hey all, I just purchased an 07 gs450h (83k) and have been tracking a misfire code that recently popped up. I brought it into a local toyota dealership and they used a borescope and found that there is quite a bit of buildup on the pistons, and under the heads. The vehicle had the valve springs replaced 20k miles ago, and to my knowledge has always used premium fuel. I'm absolutely devastated by this. I was under the impression that this issue was resolved with these vehicles. I'm hoping Lexus will help me out with this, considering I just did a pre purchase inspection with them less than 500 miles ago. If they are unwilling to give assistance for a reasonable price, what are my options here? Is there a best way to go about this? This is my first Lexus after numerous Toyotas, and it's leaving quite a sour taste, so to speak.

ibidu1

iTrader: (1)

I remember you said the issue in that it was intermittent, and that prior the dealer played with the coils and the car cleared up and ran good for a couple of weeks. Now this mechanic is stating that your issue is carbon related? Too me I dont think this mechanic at the dealership is properly diagnosing your car.

But none the less, is the car burning oil? If it isnt then it should be too difficult to clean. If anything positive is that because of the added carbon the car was more likely babied and not driven hard.

Here are things that you can do yourself that will not break the bank.

1. replace the pcv valves, super easy to do and its a cheap item.
2. Buy 2 cans of traditional seafoam the kind you pour

You want to do an induction cleaning with the seafoam. Run the car hot for awhile to make sure it is heat soaked, then pop the engine open, pop off the top engine cover. Not sure if your GS450 has a access blanked off nipple on the intake manifold or not. But if it does remove, find a small section of tube or vacuum line that will fit on that nipple. Grab a coffee mug and pour 1/3 of a cup seafoam into it, and with the engine running you will get strong vacuum on that vacuum line. Let the car slowly suck in the seafoam, to the point that it barely stubbles an idle. You will see a lot of smoke out of the tailpipes. But do this until you finish the cup, then turn off the car and let it sit for 30min, and then repeat until you finish both cans. Once you have finished let the car idle out to clear the engine of all the chemicals. Once it has cleared, take it on the highway and drive it hard

Alldatjazz

Hey thanks for all your replies so far, I really do appreciate it. The technician checked all the basics, (plugs, coils etc) and after having it back for a while the codes came up again. I asked him to do a bore scope and leakdown test. He scoped it for carbon and said "by Toyota standards, it's alot, but I'm not exactly sure what Lexus standards are. If it was a Toyota 86, it would be in our shop right now" of carbon on the piston heads. He said it looks like some chunked off recently.

In his defense, he's been very upfront with me and is definitely knowledgeable. I think this is just a tricky misfire to diagnose. It's apparently also intermittent/minor according to techstream.

The leakdown test was within specs and consistent so supposedly no issue there. I'm going to wait to seafoam etc, because I'm waiting for a call from Lexus Corp to see what we can do to rectify this professionally. If all else fails, I guess I'll seafoam it. I've had varying degrees of success with it, so we'll see.

This is just feeling like a kick in the nuts, though. I specifically tried to avoid this by getting the 3.5 fse. And getting it PPI'd at Lexus. I specifically asked about carbon issues. According to CL and Lexus techs, this is not supposed to happen. Especially at 83k. But hey, once again, I really appreciate your help. Sorry for ranting

ibidu1

iTrader: (1)

There is a good mechanic that I know if in central Pennsylvania, his specialty is tracking stuff like this. If its not to far from you, you should consider it, and hes pretty good at keeping cost low.

Alldatjazz

Unfortunately I'm in Chicago, but thanks for the offer.

Lwerewolf

Dual injection, so I'd run it with cleaners for awhile (bg/archoil/amsoil/redline/whatever has PEA). Seafoam/ATF+acetone/other engine soaks are a lot more aggressive. If you do a soak, change the oil afterwards.

Carbon buildup can happen on all engines. Short trips, flooring while cold, combination of both, more things. Port injected engines clean it up easier.

As others said, PCV valve just in case.

Standard readings for carbon buildup on bobistheoilguy and so on apply. Keep in mind that 100% throttle = direct injection only.

Some people do two-stroke oil in the fuel tank, don't think it's a good idea... unless it doesn't have anything that can poison o2 sensors/cats (phosphorus?) but I'd do my research well before thinking about it.

Good luck!

ibidu1

iTrader: (1)

Never heard of people running 2 stroke oil in a gas engine. We used to run atf fluid (1 full qt in a tank of fuel) in diesel trucks, that used to help free up stuck fuel injectors. I think atf is better then 2 stroke as atf as cleaning detergents. But I still wouldnt recommend running either in a modern gas engine unless if it was a minor dose.