|01-06-2010, 09:38 AM||#1 (permalink)|
Join Date: Feb 2009
O2 Sensor replacement
I'm not as technical as most of you guys that are active posters on the forum, nor have I done as much DIY work on my truck, so bear with me.
I have heard many of you talk about the possibility of a bad O2 Sensor being the cause of poor engine performance, poor fuel efficiency, etc. I have never replaced one, and don't even know it's location, but do understand the basic principle of its purpose.
I have for some time experienced poor gas mileage and it also seems that I have to push the engine harder for it to perform day to day as it used to. I have been through many things in my head that may cause this: filthy TB (has been cleaned), dirty MAF (cleaned, water in gas (added seafoam, actually to crankcase and gas tank), and a number of other things.
My question, how would I know if the O2 sensor is bad? I know it would throw a code, and it hasn't yet, but what's the possibility that it's going bad and hasn't thrown any codes? I guess it is still possible that there is a problem with the cylinder heads, but the dealer won't do a compression test on them unless the CEL comes on, and even then, being out of warranty, it would probably still cost me.
Any thoughts from anyone? I'm at a loss here and don't know what to do next. The dealer is increasingly uncooperative. Should I just pay for the compression test? Should they be doing that for free since the symptoms could be related to the head issue? Also, what's your dealer usually charge for diagnostics? Mine wants 95 bucks!!!!
|01-07-2010, 01:50 AM||#2 (permalink)|
Join Date: Jan 2007
Location: Baton Rouge, Louisiana
Re: O2 Sensor replacement
Normally when O2 sensor go bad, the tip (that protrudes into the exhaust pipe) burns completely off and throws a CEL/MIL code. But the vents on the tips can become clogged and it may or may not throw a code, but the force it takes to get a seized sensor off to check for clogging can damaging the sensing tip (happened to me on many occasions with other vehicles). Although not mentioned above, I assumed you cleaned or changed your air filter. If not, give that a try. The dealer is not going to do anything for free unless they caused the problem at the site. Even with warranty work, they charge GM or your extended warranty company for diagnostics and labor costs. If you don't feel like doing the compression test yourself, and since your warranty is gone, I would get it done at a reliable repair shop close to your home. This way, you can get updates easily on it, the price will most likely cheaper than the dealer, you won't feel as cheated because someone else besides the dealer is getting paid, and if the diagnostics from the shop show that it's is related the the TSB / modified recall dealing with the cylinder head / valves, you can then use that paperwork proving it to force the dealer perform the repairs. This repair is covered free of charge for 2004-2006 models for 7 years / 100,000 miles, which ever comes first. But the 7 years starts from the date the "vehicle is placed in service" not the year model. So you have more time if you bought the vehicle at the model's year end and don't drive it often.
2006 Black ZQ8 3.5L LT CC
K&N air & oil filters
PowerAid throttle body spacer
MBRP single side exit stainless cat-back exhaust
Jagsthatrun transmission crossmember
Kenwood KDC-X990 Headunit
Kenwood KAC-X501F - 4 Ch. Amp
Kenwood KAC-X401M - 1 Ch. Amp
Polk DB650 2-way coaxials in front and rear doors
PowerAcoustik Tweeters in front doors
Two 10" Pioneer Premier shallow sub
Custom downfire dual 10" sub box (under rear seat)
Radioshack mini mobile CB hidden in center console
Mobile phone type CB antenna (on back glass)
50% tint on front doors and 20% strip on windshield.
|01-07-2010, 11:28 AM||#3 (permalink)|
Join Date: Feb 2009
Re: O2 Sensor replacement
Thanks a lot for the response Solow. Are our trucks equipped with two O2 sensors? Also, would you consider it worth it to try to check the sensor, and is it difficult to get to as well as difficult to remove? And I have changed the air filter in probably the last 12,000 miles or so, I've checked it recently also, it's not dirty.
I have no idea how to perform a compression test myself, nor do I have the equipment, but how much would you think an independent mechanic would charge vs. the dealer? I know it would be my luck that anything the dealer attempts to diagnose would would not result in them finding anything, sticking me with the cost of the test (this happened recently with them taking a look at my front left disc brake, they found nothing, charged me for looking, see other post). Anyhow, I did luckily buy my '06 in september that year, and only have 43k on it, so that's not too bad.
Thanks again for the suggestions!!!
Oh yeah...what's a new O2 sensor run, and am I any better off with the OE part, or is aftermarket just as good and cheaper?