ARISTOFIED

I put some thought into this and with each O2 being $100+ I'm really looking into bypassing them altogether, I have changed all Bank 1 sensor 1+2, and the Air Flow Meter, and still car runs fine then goes back to idling like crap. It backfires and looses all power, then runs good while running (35+ mph) but when it comes to a dead stop the car jumps from 1000-500, and then from 500-800 rpm, and i don't really know what is wrong with it. My question is this can I use a O2 simulator to bypass the O2 sensors altogether?? I as well tried changing spark plugs and oil, also installed stock airbox and got new filter. I changed all spark plug wires and 1 Igniter that probably had nothing to do with the problem. Any input would be appreciated, thanks from one FRUSTRATED enthusiast....

Och

iTrader: (3)

You don't want to get rid of O2 sensors, they are essential to proper air/fuel ratio. The O2 simulator that you mentioned is usually used to get rid of the secondary (past cat) O2 sensors, when getting rid of cats, but the primary O2 sensors are a must. That being said, have you checked your ECU?

ElitistK

iTrader: (4)

hmm check for a vacuum leak.

my car runs perfectly fine with no o2 sensors, and my piggyback isn't even installed in the car.

ARISTOFIED

Okay, so here are the latest news, i swapped the O2 sensor on the midpipe, it worked for 1hr then went back to doing the funny business, i checked for any signs of vacuum leaks and found nothing. The car has 110k miles, and ran fine up until 3 weeks ago after the heavy rainfall in SoCal, i went through a couple of the lakes that build up in the San Fernando Valley near CSUN, and i saw all types of steam come out of my car and thought nothing of it until the next morning when the car was not running right, it kept hesitating. I changed out what the local mechanic said it had wrong, he said O2 and MAF, changed those out and car ran fine then goes back to idling like it wants to die, give it some gas and it idles perfectly, then sits for 5min and goes back to wanting to die, I noticed that it happen a lot more when its on Drive, shift to neutral and idles good, i unplugged all O2 sensors and runs fine but still does that, Im still a lil stupefied on this situation, anyone that can point me in the right direction would help, I am going to make an appointment at Lexus tomorrow and see what they find, hopefully its not too serious.

pimplux808

may i ask why u guys run no 02 sensors?
and doesnt it give u shietty gas mileage?

i jus wanna learn somthing new .....

aloha

19psi

you have to run the front 02 sensors for the ecu to be able to calculate proper fuel injection. the rears you can get rid of with n o ill effects aside from a cel.
sounds like you have a weird problem that would be well worth paying an hour labor to the dealer to diagnose. some things are just easier with the factory scan tool.

ElitistK

iTrader: (4)

the 2jz is a real odd-ball. the engine will run properly without the sensor 1s (b1s1 and b2s1). It will run on an internal fuel map when it detects an absence in the o2 sensors. in fact, many guys that go FI with safc take out all the o2 sensors.

are you 100% sure that you don't have a vacuum leak? what about connecting something that you are not suppose to? because this happened to me twice. First time was because i messed with the TPS, second time was because i connected somethign I wasn't suppose to (which in a sense makes it a vacuum leak)

dirty/junked maf will attribute to this as well.