Rx300: Jumping, And Stumbling, And Stalling (oh, My!)

[ukfan4sure!]

STILL UNResolved! See posting below!

First of all; thanks for letting me in the forums. I am a regular on Bimmerforums (3100 posts), but the Lexus scene is pretty new for me.

First, I purchased this RX for my wife about a year ago. It had relatively high mileage (92K) but the price was great, so I bit.

It's been a perfect car until about 4 weeks ago when it took a spell of an apparent mis-fire with the tach jumping erratically (no change in engine speed, though), the car stumbling several times, and eventually dying.

It threw a code (but it said something about the Bank 1 sensor) and the VSC light.

For two straight weeks, it ran like a Singer sewing machine; no problems, so I threw the PO codes away and I don't remember the exactly what they were. I tossed it up to bad gas.

But several days ago, it acted in the same way again. I took it over to the local parts store to get the codes again, but before I could get there, the lights cleared (would they still be stored in memory?).

Anyhow, now I began getting worried about this PITA intermittent situation with the wifey driving it.

Well, yesterday it did it again and this time it stranded her. Jumping, stumbling, erratic, wildly swinging tach with no engine speed change (like it's electrical in nature). It seems that the problem subsides if the car sits for a while as the last two times it has done it, the next day it runs fine. Geez!

Anyhow, my question is this: Is the extra lead off of the battery (covered in the looser plastic sleeve) for all of the electronics? Does it have a link fuse under all of that? I felt down the length of it and I think there must be something inside as it doesn't just feel like solid cable. Could that be where an intermittent/corrosion problem exists? Is there a cable harness I can remove and reconnect somewhere?

Before someone mentions it, the terminals are tight and clean on the battery.

I did several keyword searches here, but to no real avail except for the mention of an "oil sensor" possibility. Does that sound pausible for these events I am seeing?

Anyhow, thanks a lot. I hope this will be "paybacks" through another forum for all of the people I help from time to time on the "Bimmer" side of the automotive world. Lexus is a strange, new world to me! Ha!!

[lenore]

I would get the codes for us so at least we can get an idea.

[ukfan4sure!]

I would get the codes for us so at least we can get an idea.

OK, I dug it out of the trash beside the computer desk (I forgot I had put them there), but I am worried that the codes are simply a secondary response to the real problem. I could be wrong.

P1350 VVT Sensor Circuit Malfunction Bank 2 -- Camshaft position sensor.

P0340 The PCM has determined that a malfunction exists in the electrical circuit for camshaft position sensor "A" (Bank 1 or single sensor).

[lenore]

sounds like the wire to the sensor got disturbed or the sensor for the WWT is bad. Someone else had that problem and the sensor is fairly in expensive and once replaced fixed the problem. Maybe someone else will pipe in.

[wwest]

"..Tach jumping erratically...."

I beleive the tachometer is driven via an output from the engine management/control ECU and tehrefore is NOT directly related to actual engine RPM. I would find the ECU and unplug and reconnnect ALL of the connectors to it.

[ukfan4sure!]

"..Tach jumping erratically...."

I beleive the tachometer is driven via an output from the engine management/control ECU and tehrefore is NOT directly related to actual engine RPM. I would find the ECU and unplug and reconnnect ALL of the connectors to it.

Thanks. I will try this, if I can locate the unit. Knowing my luck, you will have to remove the engine to get to it.! Ha@

[KBRX330]

Replace your cam position sensor. You can check the connection but the sensor is probably bad. BTW, 92k is not high mileage on one of these as with proper maintenance you can expect 200-300k out of this vehicle.

[ukfan4sure!]

Replace your cam position sensor. You can check the connection but the sensor is probably bad. BTW, 92k is not high mileage on one of these as with proper maintenance you can expect 200-300k out of this vehicle.

Yeah. The bank 2 cam sensor was flakey. It would act up at random times, but I finally came to the conclusion it was heat related.

$70 later, I am back on the road! Thanks to all for your help!!

[ukfan4sure!]

Replace your cam position sensor. You can check the connection but the sensor is probably bad. BTW, 92k is not high mileage on one of these as with proper maintenance you can expect 200-300k out of this vehicle.

Yeah. The bank 2 cam sensor was flakey. It would act up at random times, but I finally came to the conclusion it was heat related.

$70 later, I am back on the road! Thanks to all for your help!!

It's back again! *&^%$!!!! I'm really getting ticked!

P0350 and p1350 again!

[sktn77a]

This is where you can let the dealer actually earn their pound of flesh! Take it in for a diagnosis - could be a coil(s), MAF, TPS, etc, etc. Just one thing - make it very clear to them that if they don't cure the problem, you don't pay for it. Otherwise they will just swap out parts until they get lucky (ay your expense). At Lexus prices, they can earn their $120/hour service rate!