rosen71

Hi there,
I had a time to "play" with the car recently, and came up to a strange situation.
As I had to replace the A/F sensors (changed them both), I managed to get my hand on Techstream software and a cable.
I run a diagnostic, and no errors were shown. That made me happy, of course.
Then I run a live test, and it shown up occasional misfire on 1,2 and 5 cylinders. I changed the spark plugs, without making any difference.
Did the test again, and no errors were recorded, but during live test, the same misfire was shown.
I was advised to change the coils, but before doing it, I would like to get any advise (if possible).
Thanks.

fastnoypi

check your rear OCV sensor. You listed and addressed the other typical causes. I doubt it is your coils.

rosen71

I will check and revert. Thanks

salimshah

I am stumped ,,, if they were on the same back 1,3,5 or 2,4,6 then OCV would be the prime suspect. When were the plugs replaced ... 110k miles is the recommended interval.

Salim

rosen71

The sparks were changed recently (less than 500 km).


I was thinking to swap the coils and to test it again.
And OCV will be checked as well.

salimshah

May I ask which brand?

With 3 cylinders misbehaving, swapping has its own challenge. With one bad it is easy (other than cylinder #3 )

Salim

rosen71

NGK Iridium.
No difference before and after the change.

salimshah

Ignoring techstream for a bit, is your CEL lit up or flashing (misfires among other things). I am questioning the validity of the data.

Salim

rosen71

There is no CEL at all, and Techstream shows no error codes recorded.
The misfire in live data is not constant but occasional, and counts when rev the engine. At idle speed I do not recall any counts.
That's why I wonder if the coils are the reason.
The other thing is the high fuel consumption (if the display readings are credible). The car is driven by the wife, city only and in a short distances. I never read less tha 21l/100 km. Once we drove the car outside the town, and for 240 km I got 12,4l/100 km with normal driving (100-120 km/h).

AnthonyMtz

Hey there, I had the same exact problem on my dad's 2001 Rx300, it's the OCV valve, it was around 55$ at O'Reillys auto parts. Now the brand was the "Dorman" one, 20k miles, 2 years and she's still going strong. By the way, just a few tips, 1. Make sure you clean the little mesh filter with brake clean when the ocv is removed. 2. Make sure it seals properly. Good luck!

rosen71

thank you guys. I will try and see what will happen.