dimitrov

Sorry guys for reopening this issue but strange things are happening...
I was reading all about this on the forum (or at least I'm thinking that it was all) but it seems I cannot find my case in earlier posts. So here is the problem on my 2003 RX300:

Daily the car started throwing mainly PO301 and sometimes together with PO300 error codes under the following conditions:

Always driving on an upward slope, with big enough speed and accelerator pedal is slightly pressed just to maintain constant speed, the MIL starts blinking. If you maintain this for a while, the MIL is ON permanently so is the VSC light.
While blinking If you push the pedal to the bottom for hard acceleration, at increasing the revs the MIL goes OFF.
The MIL never goes ON when I drive on an downward slope, despite of the same position of the accelerator pedal (slightly pressed).

No rough idle or noticeable lose of power at all. The engine is running normally except that when the car is stopped the revs drop low (about 500 rpm) when you shift to D. The revs turn back to normal (about 850 rpm) when the shifter is back on N or P. They also return to normal if being on D, you switch the headlights on.

What I did until now:
1. Coil and spark plugs rotation. No luck. Always PO301 and PO300.
2. MAF sensor cleaning.
3. VVTi (OCV) oil filters cleaning.

At last I'm thinking to pull out and clean the VVTi valves itself but I doubt that there will be any change because the filters were absolutely clean...

In my opinion the issue is more timing related than coils or spark plugs, so I suspect that the VVti's are gone, but I was hoping for any similar experience or advice before jumping into the deep water, blindly changing parts on a trial and error principle.
Thanks in advance

Drcoffee

Fuel injector. Swap 1 and 3 and see what codes pop up

dimitrov

Thank you for the reply. I'll try that though you know what it takes to reach again cylinder 1....
Make sense to be injector because I forgot to mention that the problem became constant after the car
was not used for a couple of weeks.

dimitrov

Unfortunately my hope lasted very shortly. I also forgot to mention that the car has an LPG and the engine behavior is exactly the same on gas as it is on LPG. As we all know, the LPG system uses another set of injectors so is hardly unlikely for them both (for cylinder 1) to fail at the same time.

zacky2020

also check injector rail and low and upper intake gasket for vacuum leaks can cause misfire po301