andrsnsm

New to the forum and needing some help please!

Four weeks ago the check engine light on our 1999 RX300 began flashing and the engine ran very rough. The next morning (a Sunday) I took it to the Firestone shop and they diagnosed the #4 coil pack as bad and replaced it. While they were there they replace all six plugs and cleaned the fuel system. Ran fine. Two weeks later, same thing happened but this time it was the #2 cylinder coil pack. Tonight my wife informs me it did the same thing today but she says it is okay right now. Have to take it to get it looked at again now. Does it make sense that coil packs would fail so closely together? What else could be causing the problem? The car has 172k miles on it and was fine until now but now I am getting tired of spending money on this. Any suggestions?

salimshah

It would make sense for coil-packs to fail if they are from the same manufacturing lot (we are talking end of life ... after years of service. I would not suggest that you go buy the remaining 5.

Salim

andrsnsm

So two of the six have failed within two weeks of each other, are you saying that if they were from the same lot they might all fail very shortly? These may all be original to the vehicle but I am not certain. I just went out and started the engine and it is fine right now but I have no faith in it now. What are other know issues I need to be aware of, I know the transmission was replaced some years back and the timing belt was changed at about 95k.

salimshah

I am not making any great revelation here. Products failure typically have a bell curve and things from the same lot, with same environment would have similar life.

My view is, RX is pretty trouble free till 60k. Sensors start going bad around 120k. Some will disagree, transmission failure do exist, but are not prevalent. If the vehicle clocks 100k trouble free miles, there is no reason to complain. 150k trouble free miles is bonus.
[that is why the base warranty is around 60k]

Salim

andrsnsm

Oh I'm not complaining about the failure of the coil pack(s) but I am concerned there may be some other underlying cause of the failures. Two (maybe three) coil packs failing within 1000 miles of each other seems odd statistically. That does not follow a normal distribution. So is there something that could be causing this other than coil packs running out of life?

salimshah

I am trying to convince you that it is not odd specially if you are @100k miles or more, and more so if you changed the plugs recently. Talking about plugs, I would strongly suggest stay with OEM.

Other than age and plugs there is no other reason I can think of for the demise of coilpacks. RX engine gets hotttt and that is why one can not compare the life with other vehicles.

Salim

kalali

Actually is makes a lot of sense. The coils are operating under identical physical environment and they probably have similar (if not identical) life expectancy by design. Theoretically all other things being equal, they should all fail within a standard deviation or so apart.

sktn77a

iTrader: (2)

Sounds like an unusual coincidence (two coils going bad within 2 weeks of each other). Your most recent problem is likely different - coil packs usually don't go bad and then get better on their own. Maybe a loose spark plug wire?

How much did firestone charge to replace the coil and plugs and clean the fuel system? (That would be close to $1000 at a lexus dealer).

andrsnsm

Wife took it to the Lexus dealer and they felt like the #2 fuel injector was sticking. They cleared the fault, suggested a injector cleaner additive, and said if it happens again they recommended replacing all the injectors at a price of $1550. While she was there she starts looking at Certified pre-owned ES's and the dealer offered us $3500 for the RX300, yea. Last night the son of a co-worker called a buddy of his that is a tech at another Lexus dealer and he did not agree with the first Lexus dealer's diagnosis but really didn't have anything to offer unless we could get the car to him to look at. I would except he is 120 miles away and I don't trust the car. There is a shop the specializes in foreign cars that I may take it to for an opinion.

The work that Firestone did cost me right at $700. About $240 of that was labor to replace the coil pack since it was on the rear side and they had to remove other stuff to get to it.

No confidence and still confused.....

bob2200

I think I would upgrade my towing insurance coverage to a 100 mile range limit and drive it over at say 50 mph. Just a thought. You didn't say it wasn't drivable, just you don't trust it.

andrsnsm

Your a funny guy.

So I took it to work yesterday and had her drive my car. I added some fuel injector cleaner and gave it a little highway time, it is running fine for now. Still don't trust it and will likely sell it in the near future.

andrsnsm

Update.....

So yesterday I borrowed a code reader and got a P0302 for a cylinder 2 misfire; this coil pack had supposedly been replaced by the good folks at Firestone. I swapped it with the #6 coil and cleared the P0302, drove it, and this time got a P0306 as I suspected I would. Went do the parts store, bought a new coil pack, installed it, now she's running fine (for now).

Now I am not sure Firestone did much of what they said they did and charged me for. First, they said the #4 coil had to be replaced and charged me lots of labor because it was a rear cylinder and they had to remove the plenum to get to it. That's interesting since #4 is a front cylinder. Then they replaced the #2 coil pack. That's interesting too since that's the one that I replaced yesterday and I am not convinced yet that the one I pulled out was only two weeks old. I am going to have to go talk with them.

AlexusAnja

That's so bad... it's these scam shops that give the other 95% of legitimate shops a bad rep.

My packs were failing around 90K also. First one blew around 97K, the next 110K, and finally 3rd one went about another 5K afterwards so I just asked for all the other changed on the 3rd trip. I have used super unleaded since, so can't really say if there was anything I could have done to have prolonged the packs. The plugs were also replaced at much earlier (60K) interval than recommended.

Hey... things break, what can be said...

thomas1

Hey, you know a coiling failing could be corrosion on the spring that contacts the plug. any resistance puts a strain on the coil pack. You need a flash light to look inside the cup and see the condition of the spring and plug. Dielectric grease added to the spring would prevent moisture from accumulating and causing the corrosion. Cleaning the spring and plug tip with emery cloth and putting the grease on would reduce the chance of this kind of failure. I live in california where the weather is not extreme and am on the original coil packs at 186k miles. But in snow country and extreme weather condensation could put more strain on the electrical system...Good luck.