Gs300 Sport Poor Acceleration(2000 Model)

[dervdoc]

newbie here people, just bought a year 2000 lexus GS300 Sport, 6cylinder naturally aspirated,automatic,

starts perfectly, no hesitations, no splutering or misfires but seems really really dead compared to wat she should be like,

the engine management light is on but will try get the code reader on her tomorrow,

anyone came across this before, maybe something simple.

[TigerFish]

Welcome to LOC

Unfortunately nothing that springs to mind without the codes, just so many reason for the light to be on.

[dervdoc]

right, i plugged in today, fault codes are as follows

P0135 Oxygen sensor circuit bank 1, sensor 1

P0141 Oxygen sensor circuit bank 1, sensor 2

P0155 Oxygen sensor circuit bank 2, sensor 1

also got more info on the history of the vehicle, both ''cats'' have been gutted, and there was a problem with engine reving and cutting out but the previous owner replaced the throttle body and this was cured but engine really lacks in power since it was fitted,

any ideas?

it seems funny of all o2 sensors to be throwing up faults not unless the ''de-cat'' has affected readings, they all seem to be pluged in tho, only thing i dont know is if these faults where actice before the throttle body was replaced and the de-cat was done,

any help would be much appreciated,

owner had access to a rolling road and she only made 136 bhp, no where near the factory 200+

never splutters, idles perfect

[dave1]

So did you buy privately? Did faults not show on test drive? Not trying to come across wrong but you must have some redress depending on how you purchased the car.

[TigerFish]

I'm assuming if it has been decat'ed, then all sensors would trip. If the ecu is tryig to cut everything back to try and get the sensor readings in scope, then that could explain the lack of power. I would've thought a decat would need the sensors disconnecting and something plugging in in their place to fool the ecu. If the ecu is trying everything it can to get the right readings, and failing, it can only assume the whole thing is knackered and go into a limp home type setting.

[dervdoc]

So did you buy privately? Did faults not show on test drive? Not trying to come across wrong but you must have some redress depending on how you purchased the car.

i took it as a trade in, new it needed work, so isnt standing me much.

[dervdoc]

I'm assuming if it has been decat'ed, then all sensors would trip. If the ecu is tryig to cut everything back to try and get the sensor readings in scope, then that could explain the lack of power. I would've thought a decat would need the sensors disconnecting and something plugging in in their place to fool the ecu. If the ecu is trying everything it can to get the right readings, and failing, it can only assume the whole thing is knackered and go into a limp home type setting.

this is basically wat i have been thinking, only way is to fool the ecu into thinking its reading perfect lambda, alot of amgles to look at

[dervdoc]

right iv fixed the blow out in the exhaust, still seems to be the same,going to look more into the o2 sensor side of things,

[ColinBarber]

if you don't have o2 sensors in place then the ECU will detect no heating element resistance and throw up the error codes you are seeing. It maybe that O2 simulators have been used to fool the ECU into thinking the O2 sensors are performing but the heating element wasn't considered.