I know a bit about reading live data (see video) but want help to pinpoint my issue.

Drivability issue:
Low power. Sluggish acceleration. Poor fuel mileage. Lots of codes.

What has been done?
Vacuum system checked and hoses replaced. New fuel pump, filter, and pressure regulator (all inside the tank).

Codes:
P0300 - Random/multiple misfires.
P0302 - Cylinder 2 misfire.
P0304 - Cylinder 4 misfire.
P0306 - Cylinder 6 misfire.
P0171 - System too lean bank 1.
P0172 - System too rich bank 2.
P1130 - Air/Fuel ratio sensor circuit range performance. Malfunction (bank 1 sensor 1)
P1150 - Air/Fuel ratio sensor circuit range performance.

I have some idea of what's going on but just want input from some people who are smarter than me.

Any input is helpful. Thanks for looking.

Video:

 

To me the issues are due to bank 2 [radiator side #2,#4 & #6]. That relates to misfires and rich on that bank ... also read sluggish drivability when you have 50% power being generated.

Since this is not happening to bank1, then all common items fuel pump, vacuum etc are not suspects.

This narrows down the scope to bank2 cam, bank2 advance[OCV], bank1 cam sensor. Was timing belt touched, if so recheck the marks at TDC. Spark plugs could be bad but unlikely to have all 3 go at the same time.

Now that you have the codes recorded, you can clear all codes and see what get set.

Salim

 

I agree with Salim, you have big problems on bank 2 in my opinion.

According to your codes you are running rich on bank 2.
But, in your video you are running extremely lean and adding +50 fuel trims(if I can see correctly).
Bank 2 AF sensor is swinging from high extreme to low extreme upon held raised idle to rapid rpm decel- this looks ok but doesn't prove a bad or good sensor, only that it's doing something and not dead.

>> The codes reported by your ecm appear inaccurate and do not match your scanner live data if your fuel trims are +50(running lean) so this may be part of the confusion while the ecm is desperating trying to maintain perfect fuel-to-air ratio but it can't, especially when revving.

One more thing- is there more to this story that lead to you replacing the fuel pump and whether thse problems happened before or after???- need all the details PLEASE...

Zoomed and still hard to see so plz confirm 100% for sure the long term fuel trim shown is +52.3(running lean) and not -52.3(running rich).

 

Long term fuel trim bank 2 is +52 at idle. I thought that was a rich condition.

I replaced the fuel pump because all the codes shared fuel delivery as a common cause. I had not run live data. I work out of town and my son sent me the codes and I ordered the parts before my trip home thinking it had weak fuel delivery.

It has new Air Fuel Ratio sensors on bank 1 and 2. I did not put them on the previous owner did. I think they are China parts but not sure.

The bank 2 02 (air/fuel ratio)sensor tested good with a resistance test but the voltage while it is running is way out of spec. I think they are supposed to operate between .2 and .9 volts.

The trims are also out of spec on both sides.

I am starting to suspect that the ECM is failing. But I am unsure.

A little more background:
I put a timing belt on when I purchased it in the spring. I have done many of them on Toyotas and I am very confident I did it right and the timing is correct. It ran well after I did it.

Since I purchased the car it has had an acceleration issue. It was very slight when I first bought it. I have felt this slight hesitation on acceleration in other 3.0 Toyota engines from the same era. I have also driven cars without the condition that had full power on acceleration. My wife was driving when it suddenly got a lot worse and the check engine light came on. It threw all of those codes in that one event. It is not safe to drive with the low power but otherwise the engine is smooth and idles fine. No blow by. 211,XXX miles

 

Bank 1 fuel trims are out a little but bank 2 is EXTREME and can be throwing off both banks on live data.
Adding +50 fuel on bank 2 is "out of control" and will make the ECM go crazy so I wouldn't comdemn the ECM yet until more tests are done.

Interested to see pics of those bank 2 spark plugs and a vacuum gauge(harbor freight) test can yield valuable info for this kinda stuff.

That's all I got, very much like to hear what others think of your situation.

 

When you have misfire, there is unburnt fuel due to incomplete burning and that will generate sensor signal of rich exhaust. ECU then reports that. I would chase misfire source and ignore the Fuel trims till the combustion issue is solved.

I would suggest explore timing, timing-advance, cam sensor. RX being finicky, I would check the spark plugs. They need to be OEM.

With two banks, one can try swapping parts [OCV are bank specific due to mounting differences].

Salim

 

My 2001 RX300 Repair manual shows PO172 System too Rich Bank 1
My 2001 Rx300 Repair Manual shows P1130 (Bank1 Sensor 2)
My 2001 RX300 Repair Manual shows P1150 (Bank 2 Sensor 1)
Make sure these two sensors are double checked. You should be able to check voltages right at the PCM. Are you still throwing these codes?

From your video Bank 1, sensor 2 should be higher in voltage while reving it up(P1130). Note my corrections to your codes. First place I would look for is sensor 2 on bank 1. Either the sensor is bad or the Cat is bad. Check sensor first. Believe it is close to cat after the engine.

 

While I am thinking of it I will include a simple drawing of the 3 cats. The cat that I think bad is the one right before the muffler. As I remember bad AF readings could indicate a bad cat. That is if the sensor is good. Last year I had to replace one of my daughters cats mounted on the engine. Don't think the PCM is bad. So again my bet is on Bank1 sensor 2 or the cat.

 

Time for new plugs and coils. Try that and report back.

 

IMHO, you are overthinking the problem. Start with the root cause first. Fix the misfire and rich/lean conditions will most likely go away.
Better still clear codes and see which code(s) pop up first.

Salim

 

Sorry I have a tendency to do that. I went ahead and hooked up my reader up to my 2001 and took a pix of the graph of the three o2 sensors. Was not what I thought. My bank 1 sensor 2 is showing different readings than the OP. So I am at the OPs service if he needs any comparisons. Graphs of all 3 are attached. All conditions are at idle.

 

W

oops. No B1S1. sorry

 

Nice live data graphing!
I was just going to ask you if you could include the B1S1 but you beat me to it!

I know I sound like an old broken record, haha
but a proper scanner is a MUST for diy or ur talking in the wind...

Add- and a vaccum gauge to make sure the engine is breathing right and detection of compression, valves, timing, and
other things that can cause misfires and poor running conditions! "Vacuum gauge you complete me". lolol

 

Agree. I don't have a gage and I should get one. This tester I have also communicates with my cellphone to special software to help trouble shoot. Still learning how to use it.

 

Assume you mean bank 1 02. If you do see my graph on my bank 1.02 the graph completely agrees with you . I believe something is not right here. It could be the heater for the sensor is not working but at any rate I feel something is wrong. Should be more responsive but your tester could be averaging values. Let me know if you want me to run more graphs from my RX300. Oh by the way I am not always right. Makes mistakes in my old age(LOL).