02 sensors

[lexus400]

I have a '92 LS with a 140k miles. Since I bought the car with 50k, I have

always had a slight hesitation at certain speeds when accelerating. I've had it into the dealer and they have done the injection cleaning service.

That really didn't help all that much. Everything had had multiple tune-up

replacements. The service writer at one point said it's emissions and common in the early years. I'm suspicious of the 02 sensors that are all original. Should I just go ahead and replace all 4 ? I have never had a check engine light come on. Other people tell me I should have reaplaced the sensors LONG ago. The car has a perfect starting/idle and acceleration. Any advice would be greatly appreciated.

Bob

[AWJ]

Torque converter. Last tranny fluid change? What kind of fluid? Consider a precision industries swap out. I'll bet that hesitation goes away.

[lexus400]

Really ? I never would have guessed transmission. It shifts perfectly thru

every gear. The fluid has been changed every 20-30k since I've owned it.

Always looks good, no leaks. I am/was suspect of the 02 sensors since they're original. If the check engine lite is off , does that mean they're good ? What does precision industries do ? Thanks...

[AWJ]

always had a slight hesitation at certain speeds when accelerating

at what speed? approaching 40mph and 3 and 4k rpm? this is typical of that year and automatics. Precision Indiustries is a performance supplier that makes an aftermarket torque converter for lexus applications. I have heard their product is excellent. If I had an automatic and was looking for more acceleration or performance off the line and through shifts - this is what I would buy first. This will alleviate that hesitation you are talking about. If your motor is running fine at idle, there are no checke engine lights or O2 codes then I would not say your sensors are to blame at all. How are your plugs and what grade of fuel do you run? You know you should be running 90+ octane at least.

Just my .02

[Supra-chargedIS340]

first thing to try with O2 sensors is cleanng them,many are replaced un-necercerily,remove them and leave them in some viniger overnight,clean the plugs and connectors aswell as this can cause a faulty pickup.....

also try looking at the airflow sensor,this could be getting dirty

[lexus400]

Good advise, I'll pull them out and try that. Where's the airflow sensor

located ? Is it in the airbox where the air cleaner is ?

[zeta]

i'm still on my stock O2 sensor. i don't see how an O2 sensor could need changing though. i thought the purpose was only to serve as a sensor to O2 so your engine is getting air instead of like nitrous :)