A question for GM mechanics.

[ARCHIVED THREAD] - A question for GM mechanics.

Posted: 12/30/2011 1:28:18 PM EDT

2002 Tahoe 5.3l 108k miles. Service engine light comes on when outside temp gets close to 0. Had the oil changed today at the dealer and they pulled the code and said it read bank one lean. They said it was likely an O2 sensor. I had the fuel filter changed. Should I do the sensor myself or drop it off to make sure it isn't a more serious issue?

Posted: 12/30/2011 1:32:44 PM EDT

[#1]

Not a GM mechanics but,...

It probably is the driver side O2 sensor, fairly easy to change. You may have to remove the front of the front driveshaft to gain access.

O2 sensors also come out easier when the exhaust pipe is hot. Rent an O2 sensor socket from a auto parts store.

Posted: 12/30/2011 1:42:57 PM EDT

[#2]

Intake gaskets leaking vacuum.

In the morning, take 1/2 gallon of water. Pop the hood and start the engine. Pour water on edges of intake manifold near the valve covers.

If it starts running rough, the gaskets are leaking. No you would not see coolant or anything leaking because coolant does not flow through intake.

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Posted: 12/30/2011 1:46:44 PM EDT

[#3]

Quoted:
Intake gaskets leaking vacuum.

In the morning, take 1/2 gallon of water. Pop the hood and start the engine. Pour water on edges of intake manifold near the valve covers.

If it starts running rough, the gaskets are leaking. No you would not see coolant or anything leaking because coolant does not flow through intake.

Posted Via AR15.Com Mobile

I was going to suggest there is an outside chance it's the air intake/plenum gasket. you might be able to spray throttle body cleaner/carb cleaner around the gasket area too, if there's a leak, the idle speed will change. I'd probably guess it's an O2 sensor though, and they are usually fairly easy to replace. If it's a vortech and if it is similar to the vortech 4.3s, take that thing and light it on fire, roll it down a hill and into a large body of water. Chevy and their Vortech 4.3 intake manifold gaskets can go straight to hell.

Posted: 12/30/2011 1:50:33 PM EDT

[#4]

do computers kick out a code for O2 sensors at 100K?

since they deteriorate over time?

Posted: 12/30/2011 1:52:10 PM EDT

[#5]

Quoted:

Quoted:
Intake gaskets leaking vacuum.

In the morning, take 1/2 gallon of water. Pop the hood and start the engine. Pour water on edges of intake manifold near the valve covers.

If it starts running rough, the gaskets are leaking. No you would not see coolant or anything leaking because coolant does not flow through intake.

Posted Via AR15.Com Mobile

I was going to suggest there is an outside chance it's the air intake/plenum gasket. you might be able to spray throttle body cleaner/carb cleaner around the gasket area too, if there's a leak, the idle speed will change. I'd probably guess it's an O2 sensor though, and they are usually fairly easy to replace. If it's a vortech and if it is similar to the vortech 4.3s, take that thing and light it on fire, roll it down a hill and into a large body of water. Chevy and their Vortech 4.3 intake manifold gaskets can go straight to hell.

Water works better than intake or brake cleaner.

Posted: 12/30/2011 1:52:59 PM EDT

[#6]

Get a Computer Code Reader from Autozone or some other Car Parts place and get back with the Codes.

Impeach Obama for the Good of the Children.

Posted: 12/30/2011 1:58:03 PM EDT

[#7]

Quoted:
Get a Computer Code Reader from Autozone or some other Car Parts place and get back with the Codes.

Impeach Obama for the Good of the Children.

He said lean bank 1 which is P0171.

Posted: 12/30/2011 2:31:04 PM EDT

[#8]

Quoted:
Intake gaskets leaking vacuum.

In the morning, take 1/2 gallon of water. Pop the hood and start the engine. Pour water on edges of intake manifold near the valve covers.

If it starts running rough, the gaskets are leaking. No you would not see coolant or anything leaking because coolant does not flow through intake.

Posted Via AR15.Com Mobile

Very interesting. It sometomes runs rough when I go through a car wash. Especially if I get the under body spray.

Posted: 1/5/2012 1:34:53 PM EDT

[#9]

Update?

Posted: 1/5/2012 1:36:25 PM EDT

[#10]

Coolant temperature sensor

Posted: 1/5/2012 1:36:58 PM EDT

[#11]

My 2000 Tahoe 5.7L had the same issue when it was -5F here and my brother (a Master ASE GM mechanic) cleared the code for me and it hasn't come back. The code said it was an O2 sensor and he said he wouldn't worry about it unless it came back.

Posted: 1/5/2012 7:21:38 PM EDT

[#12]

Quoted:
Update?

I haven't had a chance to work on it yet. Don't know when I'll get to it now, I'll just drive the Jeep. Thanks for your help.

Posted: 1/5/2012 10:16:50 PM EDT

[#13]

Get some contact cleaner and clean you mass air flow sensor. Then drive it for a bit and if the code clears you are good. If not then something else oxygen sensor or vacuum leak. 70% of the time it is a dirty maf or air filter especially with clowns that had k&n's with a gallon of oil on them.

Posted: 1/5/2012 10:19:12 PM EDT

[#14]

O2 sensors will cough up a code whenever they feel like it.. I wouldn't worry one bit about it.

[ARCHIVED THREAD] - A question for GM mechanics.

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