SamTyler

I have a 1998 Tahoe 5.7 4x4 2 door that keeps blowing the right side O2 sensor in front of the cat. It has been replaced by the gm dealer 3 times and it normally lasts about 1 month and gone again. The truck does not smoke or burn oil between changes. The dealer just told me that I would need to rebuild the engine to fix the problem. The engine runs perfectly smooth until the check engine light comes on and then the system starts overloading the fuel to the point it almost turns off. It burned 30 gallons in less than 100 miles the last time. I am lost at this point to figure out what is wrong. Can anyone help?

Thanks

usamarshal

Sounds like the stealership is up to its old tricks again...is the truck running rich all the time? Reason I ask is because I had to get a new FPR because I was only getting like 10 miles to the gallon...you can do a simple pressure test to find out...once I replaced that I was golden...I would also do some routine maintenance if you havn't already...plugs, wires, rotor, cap, fuel filter, air filter, clean the EGR valve, etc... See if that works for you...not sure why you would have to rebuild the engine if its not burning or leaking anything...the 350 Vortec engine really does kick ass...just have to watch out for the FPR and intake gaskets at times...good luck man!!!

GMMerlin

I have never seen a vehicle "blow" an O2 sensor.
What is wrong with your truck? SES light, runs bad... what is the code it sets?
Lets get some information and maybe we can come up with the root cause

__________________
Why do you never have enough time or money to do the job right the first time, but enough time and money to do it again?
Got all the certifications
25 years ASE Certified Master Technician
GM WCT
Yea..I work at a DEALERSHIP....got a problem with that?

SamTyler

Yes the light comes on, only throws code for O2 sensor bank 2 sensor 1. Sometimes the light is solid and sometimes it blinks. Suprisingly it depends on the speed on how bad it smokes. Max speed is about 65 at the worst.

While it still runs somewhat, it is flooding so bad that you can't see the cars behind you.

When I said it blows the O2 sensor, I mean the dealer says it has to be replaced each time bacause it is now bad.

SamTyler

Yes the light comes on, only throws code for O2 sensor bank 2 sensor 1. Sometimes the light is solid and sometimes it blinks. Suprisingly it depends on the speed on how bad it smokes. Max speed is about 65 at the worst.

While it still runs somewhat, it is flooding so bad that you can't see the cars behind you.

When I said it blows the O2 sensor, I mean the dealer says it has to be replaced each time bacause it is now bad.

GMMerlin

Sam,
Believe me, I am not trying to give you a hard time, but I am trying to gather as much information as I can to give you some solid advice...so please bare with me.
There are 5 codes just for the O2 sensor..each one means something different, so it would be helpful to know the number.
Also an O2 sensor code will not cause a blinking SES light..so if the light is blinking, you are setting a misfire code also.
It is possible that the O2 sensor is not the cause of the problem, but the code could be a result of something else.
Also since the sensor has been replaced numerous times, maybe a wiring issue is the cause or possibly some sort of fuel contamination is schewing the O2 sensor.
See if you can get the codes off your copy of the repair order and hopefully we can come up with some ideas to what is the root cause

__________________
Why do you never have enough time or money to do the job right the first time, but enough time and money to do it again?
Got all the certifications
25 years ASE Certified Master Technician
GM WCT
Yea..I work at a DEALERSHIP....got a problem with that?