Rx300 Misfiring/lack Of Power

[jimevans501]

I have a 2001 RX300 that I have driven for several years, the car has now done more than 144k miles and so far I have been very pleased with the car and Lexus service. Several weeks ago I started experiencing a problem when the engine warning display started flashing, then went on fully, quickly followed by the Vehicle Stability Check (VSC) light. Lexus dealer read the error code as a random misfire on several cylinders. The problem has progressed with the symtoms now being an intermittent lack of power, all the plugs and power packs have been replaced, the engine warning light does not now flash but the VSC light is on continuously. The lack of power "feels" as if there is no fuel getting through. The car had an LPG conversion some 80k miles ago and the problem manifests itself on both fuels. Lexus suggested compression testing and this showed a small reduction on one of the front three cylinders but I am sceptical that this is the cause of the problem due to the highly intermittent nature. Error codes being produced still say random misfire. I wondered if any other owners had experienced any similar problems or could suggest a solution?

[ColinBarber]

Can you list the error codes?

[1newlexusowner]

I have a 2001 RX300 that I have driven for several years, the car has now done more than 144k miles and so far I have been very pleased with the car and Lexus service. Several weeks ago I started experiencing a problem when the engine warning display started flashing, then went on fully, quickly followed by the Vehicle Stability Check (VSC) light. Lexus dealer read the error code as a random misfire on several cylinders. The problem has progressed with the symtoms now being an intermittent lack of power, all the plugs and power packs have been replaced, the engine warning light does not now flash but the VSC light is on continuously. The lack of power "feels" as if there is no fuel getting through. The car had an LPG conversion some 80k miles ago and the problem manifests itself on both fuels. Lexus suggested compression testing and this showed a small reduction on one of the front three cylinders but I am sceptical that this is the cause of the problem due to the highly intermittent nature. Error codes being produced still say random misfire. I wondered if any other owners had experienced any similar problems or could suggest a solution?

I had the same problem and if your only getting say 5 miles to the gallon then Aberdeen Lexus told me it was the o2 sensor there is 3 of them and its best to replace all 3 at same time hope this helps m8!

Begards,

B

[ColinBarber]

There is no reason to replace all three sensors. Just the one that is giving the error. Sounds like the dealer wanted to make some more money.

The series I RX uses air/fuel ratio sensors rather than standard O2 sensors so you need to be careful to obtain the correct ones if you purchase aftermarket ones.

[jimevans501]

I have a 2001 RX300 that I have driven for several years, the car has now done more than 144k miles and so far I have been very pleased with the car and Lexus service. Several weeks ago I started experiencing a problem when the engine warning display started flashing, then went on fully, quickly followed by the Vehicle Stability Check (VSC) light. Lexus dealer read the error code as a random misfire on several cylinders. The problem has progressed with the symtoms now being an intermittent lack of power, all the plugs and power packs have been replaced, the engine warning light does not now flash but the VSC light is on continuously. The lack of power "feels" as if there is no fuel getting through. The car had an LPG conversion some 80k miles ago and the problem manifests itself on both fuels. Lexus suggested compression testing and this showed a small reduction on one of the front three cylinders but I am sceptical that this is the cause of the problem due to the highly intermittent nature. Error codes being produced still say random misfire. I wondered if any other owners had experienced any similar problems or could suggest a solution?

I had the same problem and if your only getting say 5 miles to the gallon then Aberdeen Lexus told me it was the o2 sensor there is 3 of them and its best to replace all 3 at same time hope this helps m8!

Begards,

B

Many thanks for the feedback. The problem does not appear to be affecting the fuel consumption, still getting roughly 5 miles per litre, just intermitently struggles to accelarate, for those old enough to remember such mechanics it is like the float valve in the carburetor occasionally gets stuck and not enough fuel is getting through.

[jimevans501]

Can you list the error codes?

Colin many thanks for the input, I dont have the details of these will try and get them in the next few days.

[jimevans501]

Can you list the error codes?

Colin many thanks for the input, I dont have the details of these will try and get them in the next few days.

Colin

I have now managed to get the error codes, they are P0300 (Random misfire), P0301 (Misfire on cylinder one), P0302 (Misfire on cylinder two), P0304 (Misfire on cylinder four), P0306 (Misfire on cylinder six), do you know if there is any way of getting any additional info on the possible causes of these codes?

[Boxbrownie]

Just a thought....not sure if the Lexus VSC (vehicle stability control) works as others but is it possible that there is an error being produced in the ECU which is fooling the VSC into cutting power just as it would if the road wheels were sensing icy/slippery conditions?

Mind you its pointless asking a garage to look into that....I imagine you'd just get a blank stare with the solution of "we'll replace the module for ya mate"

[paolo137]

I'm getting the same warning lights (engine+VSC), but the car seems to perform normally, both in fuel consumption and power available.

Rx300 mark 1 has some 88000 kms on, petrol only.

I've had the ECU read by my mechanic, who's not official Lexus but has a software which can interface with the rx300, and the result was "lean fuel mixture in bank 2".

First time he just switched the alarms off. Now we've tried to have all the parameters of the engine to self-adapt thoroughly.

Should the warnings appear again, the mechanic was planning to swap the two lambda sonds in order to see if we get the error on the other bank of the engine. That would obviously mean that one of the air/fuel sensors is getting wrong readings.

I would appreciate any comment or suggestion on the issue. Many thanks!

One more thing: which one is bank 1 and which is bank 2?

[mity]

I have a 2001 RX300 that I have driven for several years, the car has now done more than 144k miles and so far I have been very pleased with the car and Lexus service. Several weeks ago I started experiencing a problem when the engine warning display started flashing, then went on fully, quickly followed by the Vehicle Stability Check (VSC) light. Lexus dealer read the error code as a random misfire on several cylinders. The problem has progressed with the symtoms now being an intermittent lack of power, all the plugs and power packs have been replaced, the engine warning light does not now flash but the VSC light is on continuously. The lack of power "feels" as if there is no fuel getting through. The car had an LPG conversion some 80k miles ago and the problem manifests itself on both fuels. Lexus suggested compression testing and this showed a small reduction on one of the front three cylinders but I am sceptical that this is the cause of the problem due to the highly intermittent nature. Error codes being produced still say random misfire. I wondered if any other owners had experienced any similar problems or could suggest a solution?

Hi, I also have a rx300se 2000 model, bought it 2 years ago with vsc and engine light on. Previous owner of car had new o2 sensors fitted before i purchased the car, but vsc still on. I ordered a new air mass flow sensor from my local lexus dealer, fitted it and problem fixed. I hope this helps.

Air mass sensor is located on the top of air filter box and is secured by screws

[paolo137]

Many thanks!

Will pass the info to the mech.