TenaClubz

Just like the title says, running around town it purrs like a kitten.. Hard acceleration it never misses. But once in a while it goes into a diefinate on and off miss seems like only one cylinder. I ran some Chevron gasoline additive and fuel injector cleaner in the last tankfull, I'm getting a lot of codes, Mostly PO-136 oxygen sensor but ironically never when it's doing it's misfire thing. Stumble-run fine, stumble-run fine, just like that at 70mph all the way to work on the freeway for 25 minutes. Then get off the freeway and POOF! all fine! Pull into the office park and a little straightaway come up , Punch it, not a miss at all. That was on the way to work today, gas mileage readout showing 8mpg. Going home this afternoon ran like a swiss watch, never missed a beat from the moment I started it, to the minute I got home. And last time it did this was around the middle of the last tankfull. It cured itself when I ran the additive in the gas until now. Wish could make it repeat .

Bad coilpack do that?

salimshah

First clear all codes.
Drive with varying conditions and check the codes again on the first onset of CEL.

Plugs should be replaced at 110K miles with OEM only.

If you get misfire code .. then try swapping coils, from a good one with the one pointed put by the code.If the problem moves then it is the coilpack. If not then swap the plugs. If the problem remains to the same cylinder then swap with a new plug.

Salim

TenaClubz

I reset the PO136 code I'm sure the oxy sensors on each bank need replacing so I'll start there and toss a set of coil packs and plugs at it. All I can do is throw parts at it. No way of knowing what cylinder is missing. Car has 125,000 miles

salimshah

Something else is going on. A misfire will produce a flashing CEL as well as a code is set [if not a hard one, a pending code is set].

I would humbly state that you are feeling a lurch or lack of gas+air ... which is technically not called a misfire as the the spark is there at the right time.

I would then suggest having the flow and pressure of the fuel line checked. Sorry I don't have the spec, but it would be in the service manual.

Dont throw parts to solve a problem. It can become very expensive and very quickly as choosing after market is not good. You can learn by gleaning the posts that RX does not like any other plug other than OEM. Once I state that, I am sure some one will come back and challenge this. But when you are having problems, it is nit wise to add unknowns in the mix.

Salim

TrueGS300

How is your oil level and condition? VVT solenoids are oil controlled and can cause a number of problems with drivabiliy.

TenaClubz

oil I changed 1500 miles ago, Valvoline with a Fram Filter

TenaClubz

I do have a lot of experience on engines, I worked for two Indy Car teams, with quite of bit of time in the dyno room. So to your point and many many many others that believes the this (or any other) engine "LIKES" a certain type of spark plug, let me assure you, this is absolute fantasy. There may be different secondary voltages on the coil that the resistance of the construction of the plug may change the way it throws a spark in a millionth of a second. But the gasolene in your combustion chamber will not care at all, it will ignite the same way every time. We have put just about every spark plug through the engines on the dyno and found there is no real difference at all in horsepower or longevity, engine per engine. It just doesn't matter at all. If you and everyone else still believes this engine has a brain that "LIKES" things, your smoking something, and you really need to share it. Only thing in plugs we found is small platinum tips tend to stay cleaner over a longer period of time because there is less area for build up to occur. So the difference between cylinders over time, is more consistent. But thats all, as goes for horsepower in a can.

Now to the issue, it is speed sensitive and doesn't throw codes when it happens. Ran fine for the 25 mile, one-way freeway ride to the shop this morning again. Starting to see a dual problem. PO136 oxy sensor code is an old pair of original oxy sensors, tossing THAT code when it does, and it's not that often, twice a month maybe three times.. But the surging I'm starting to look at not the engine, but the transmission. Never happens at in city speeds remember , stay tuned

salimshah

Respectfully, I am entitled to my opinion and you are entitled to yours. Only thing I will add is, it is your vehicles so you are the boss. If you really want to try it out, put in a set of Bosh [good plugs but they dont know Japanese ]. Trust me on the other thing too .. a misfire will give you flashing CEL and will trigger a code. As an extreme example, if you run out of fuel, the flashing CEL and misfire code will not be set when the engine is trying to run. I am no mechanic and have much limited experience and I have many limitation.
Keep us posted on what you find.

Salim

TenaClubz

Yes you're entitled to your opinion, but I can only rely on proven facts. Your opinion is just that, as in someone just saying something on the internet (which we all know what your referring to is at best just a guess) . Fact; automobiles don't "think". Their spark plugs don't "speak" Japanese or German. Don't try to educate the unknowing without facts. Fact is there is no difference between using your Lexus spark plugs, or My NGK's or Denso or for that matter you suggested Bosh (Uh buddy; it's spelled Bosch). Ok you know why this is? Because your Lexus plugs are either manufactured by either NGK or Denso. There was even a time when NGK's were even manufactured under contract by Bosh (oops, sorry) Bosch! Bosch spark plugs are made in " Bamberg is still the primary plant for Bosch spark plug production and sets standards for all other Bosch spark plug plants. Bosch factories in India, Brazil, China and Russia" Denso has manufacturing complexes in India, Mexico and Indonesia. the starter for my Ford pickup is a Denso Starter made in Thailand. Last I checked there is't too much Japanese spoken there.

So there is your story on JUST using Lexus plugs because there is just no other equivalent. When further review shows they are exactly the same plugs produced in the same plants by the same company. Case closed

I'll keep everyone posted, really paying attention to the transmision, particularly a slight stuttering on power-on up shifts. Might be some sort of high gear drive issue.

salimshah

Thank you for the correction.

Salim

carguy07

My cars like certain plugs.

TrueGS300

This feeling of liking certain plugs comes from the ecm/pcm learning runability parameters. After replacing a set, disconnect the battery and do a computer reset. The car will start over and learn its best smooth idle, fueling pulse width, and ignition advance etc. I like to use NGK myself, however I'm not a believer in cars liking a certain plug either. Any plug with the same gap has no choice but to fire when powered by the coil. There's nothing magical happening there. It's just an air gap. The more "powerful" spark people are after comes from the ignition system and is determined by the coil driver in the pcm in effect determining dwell time. This can slightly be accomplished by increasing the spark plug gap but at the sacrifice of smoothness at idle.

My reason for liking NGK is that they have a much tighter control over acceptable misfire rate. All plugs do fail to fire here and there. NGKs have been tested side by side with many plugs and have been proven to be the most dependable plug manufacturer in existence. I think I read one time that AC Delco had an acceptable misfire rate of up to 20% of the time. So basically All cars would "like" a set of NGK plugs better. Even European and Domestic cars because an NGK replacement simply misfires less.

salimshah

The issue at hand is different and the thread has/is drifting towards the science of spark plugs and can get into which plug is superior. I have refrained to engage more as it would tend to sound defensive or worse argumentative when the OP is firmly of one opinion which is different from mine.

Back to the purpose of the thread, misfire occasionally at high speed.
1. Possibly lack of spark or timing:
Replace plug(s)- coil etc. Op seemed to be on this track.
My suggestion replace with OEM make and number [over the years people have reported problems with other brands in RX]*
Do not replace coil-packs as a misfire will be accompanied by flashing CEL and error code.
2 +
Fuel starvation, OCV, transmission etc can produce lurches.

Salim
* Some members like Lexmex (who I respect tremendously) have successfully used other brands of plugs. My suggestion is based on the fail-safe approach. Once the occasional lurching is fixed, then venture out and try different plugs... controlled experimentation.

TenaClubz

Bravo Sir; very well said ,
these people have been brainwashed into thinking there cars are somehow human, good greif!

tiguy99

Wonder how the OPs car is doing after the last couple weeks.
Perhaps the problem is still ongoing or has been fixed???

Would love to know what happened