Hello fellow CL members...

I am in urgent need of your expert help with my 99 rx300...

It is idling rough, and running rougher... i have code for running rich, random misfire, and misfire on cylinders 2,4,6... mechanic at first said coil pack.. but after reading more.. it seems unlikely three coils die at the same time... ive read about Oil control Valve being a possible issue.. the truck will be misfiring and running rough... if you push the pedal.. it will kick back and go like stink for a bit.. then when i get to lower rpm.. it will run rough again.. this happened last week for about 5 mins only misfire #2..then went away for a bit now has returned worse then before.. with misfire #2,#4,#6



I cannot be without my truck as i work in it on a daily basis... im taking to to the mechanic tonight... but he always suggests i come to the club lexus and check the forums for help since you guys have been life savers more then once on this particular vechile...


So symptoms are rough idle, multiple misfires... codes for misfires 2 4 6 and a rich system...

Please any help greatly appreciated... i will always continue to finish this thread with the solution for future users benefit like i have with many of the issues ive come across with this truck..


Thanks in advance..

Leines

 

Since 2,4,6 are for the front bank, I suspect only one of those coils is bad.
You can try swapping one of the coils, with one of the one's in the back.

Since you mentioned that for 5 mins, you had a misfire on #2, i suspect that's the coil that's gone bad. If one coil goes bad, it's possible for it to set off a code for other cylinders misfiring.

So, basically try swapping coil on #2 with another from either 1,3, or 5.

 

ok so your saying that if 1 coil goes back across the front... it will misfire on all three... the reason i ask is that i was reading that the coils are individual and that three failing at once is very unlikely...
im going to run out to the truck and get the code numbers again... ill report back in 5 mins

 

So the reader says 10 codes.. but i think maybe 5 are pending and 5 are hard maybe.. but im not sure thats a guess since they repeat.. in order

1/10 - P0172 Rich bank 1
2/10 - P0300 Random misfire
3/10- P0302 Misfire #2
4/10 - P0304 Misfire #4
5/10- P0306 Misfire #6
6/10- P0300 Random Misfire
7/10- P0302 #2
8/10- P0304 #4
9/10 - P0306 #6
10/10- P0172 Rich Bank 1


Any and all help is greatly appreciated...the mechanics first thought was coil pack.. its going in tonight i just like to arm him with as much information as possible before he starts... and this place is a cornacopia of awesome for this truck.

 

Clear all the codes, and see which one comes first. As the one that comes first is usually the culprit.

And, yes it's possible that one coil can trip multiple misfire codes.

 

well last time it was only #2... i cleared the code because it seemingly went away.. it was two thursdays ago... now its come back with more then #2 so i believe that would be wear to start??

any idea on the rich code? would that just be caused because of the fuel being pushed down the misfired cylinder into the exhaust??

When i search online for this combo i read a lot of the Oil Control Valve... thoughts?

 

Yeah, I suggest starting with coil #2.

Yes, the "rich" code is just there due to the misfire, that will go away once the misfire issue is resolved.

It's possible the OCV is at fault. You can try cleaning it.

 

Thanks... im going to drop it off at the mechanic tonight and he will work at it tomorrow... since he is already on the path of the coil... ill let him go with that.. and mention the Oil control valve as an option...

I think i will also get my IACV cleaned just to be safe while its in...

Im thinking i might be in order for some O2 sensors as well after all these misfires.. im sure they are taking a beating...

 

well the mechanic started with coils... they didnt seem to be the problem,,, he rebuilt the fuel injectors... orings were hard but this also didnt fixed the issue...

the codes were cleared... and the P0172 was the first to return... followed again by the p0300 p0302 p0304 p0306..... the car is running badly.. misfiring... if i hit the gas.. it will take off like a bat out of hell... .. it ran fine for and hr at the shop..fine on test drive... then did this again.....

I just pulled the neg cable... and tried to clean the MAF with some rubbing alcohol... i dont have contact cleaner and it didnt seem dirty enough.. it was recently cleaned about three months ago by a toyota dealer...

Im a bit stumped... the mechanic is now on vacation in florida for spring break with his kids....
the more and more i read about it... im thinking it would be oxygen sensors and MAF.... but ive read threads about Oil Control Valve...


Thoughts HELP PLEASE??????

 

I would have thought a coil failure too. Absent that guide says:

P0172
P0175

When air fuel ratio feedback is stable after engine warming up,
fuel trim is considerably in error on LEAN side
(2 trip detection logic)

Trouble Area


Gas leakage on exhaust system

Fuel line pressure

Injector leak, blockage

Mass air flow meter

Engine coolant temp. sensor

A/F sensors (bank 1, 2 sensor 1)

 

i had the same misfiring codes and i went away by replacing the Oil Control Valve or VVTI oil valve.

 

can you explain to me a bit more about your symptoms.... the car will run fine it seems for hours.. then randomly... it will be laggy, misfiring... if you punch the pedal.. eventually it will just take off... the transmission seems to be shifting fine.. i dont think its a transmission problem..


How much was the Oil control valve.. and where did you end up buying it... i havent been able to find them on ebay etc.... can i use sienna or camry highlander OCV???

Cheers

 

Ok, so i talked to the local toyota mechanic today... and he said that the OCV would throw its own code... that the 172 rich is the A/F sensor behind the cat... they run $300 from toyota here in canada. he said it will cause the misfire...and that i should also change the plugs because of the condition they have been running in...
Im thinking i might have to order the part on ebay... ive read a number of times that i should stay away from aftermarket parts and stick with OEM.... is that the concensus?

Cheers

 

Yes, stick with OEM.

IMHO: An A/F sensor will not make a car misfire, at least not in an RX. But, I guess anything is possible. lol

 

see thats what i was kinda thinking as well.. but he said it will cause a very rich condition.. and will cause the misfire... when i mentioned the OCV to him.. he didnt seem to think that would be the problem without throwing a code on his own... i also mentioned a MAF, and he didnt seem to this that was the cause of it either..
this was one of the toyota service managers at a dealership that is a customer of mine... i will try another one tomorrow and see how the advice changes...

im thinking i will need to ebay... it looks like some sellers wont ship to canada... just my luck.. lol