I had to swing by Autozone today to pick up a cap/button for my Blazer and I just remembered o2 sensors.

Now for my truck I believe that there are 4 of them. 2 pre/ 2 after. I have never changed them. I repeat never changed them. When is a good interval to do this and what type of results will occur after the change?

Currently I have new wires, plugs, exhaust, cold air intake, and soon to be cap/button.

I know that they control how the engine tunes the fuel mixture ( unless I am wrong).

Is ths one of the most neglected items?

How many miles on them?

Any major problems which might have worn them out prematurely?

tuneups kept up to date over its life?

The recommended interval is 100,000 miles, however, the range that they are effective is pretty big. Some people experience problems with them sooner and notice a big improvement in performance when changing them, and some people can go far longer. I've seen them go almost twice the recommended interval with little to no problems.

The results you get depend on how bad the old O2 sensors were.You may not notice any difference, or the differences could be huge.

Well my Blazer has 131k miles on it.

I just really couldn't tell what the failing o2 sensor symptoms would be.

What interval has everyone changed theirs at?

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There have been no issues with the engine. Tuneups have been up to date except for the cap/button. I am long overdue for that. Regular oil changes, new radiator and engine flush. etc etc.

The front end and o2 sensors are what I need to get working on, but if I don't have to replace the sensors yet then I won't.

some symptoms of bad o2 sensor(s) would be bad gas mileage, engine missing (PO300 for example), excessive gas smell. these are similar symptoms of a bad fuel injection spider and a clogged egr.
is your truck running bad right now?

I will have to get back to you on this after the cap/button change. If it still runs bad then yes I am having issues.

cap and rotor will make a diference.

Will O2 sensor make fuel injectors go bad also? I'm also still having o2 sensor problems. Bad gas smell, horrible skipping, flashing service engine light. Any ideas?

Selena

Selena - What year is your Blazer? And, what have you done to it - tune up, etc?
Knowing the year and history will help us to help you.
billibong

It's a 96 4x4. We've put new plugs, plug wires, coil, distributor cap & rotor button, 2 injectors. Just about everything known that would cause this thing to skip. Now, they are telling me that the o2 sensor has probably caused the NEW injector (put on yesterday) to go bad. If you need any more info, I'll be online.

Thanks for the quick response!

Selena

I had to swing by Autozone today to pick up a cap/button for my Blazer and I just remembered o2 sensors.

Now for my truck I believe that there are 4 of them. 2 pre/ 2 after. I have never changed them. I repeat never changed them. When is a good interval to do this and what type of results will occur after the change?

Currently I have new wires, plugs, exhaust, cold air intake, and soon to be cap/button.

I know that they control how the engine tunes the fuel mixture ( unless I am wrong).

Is ths one of the most neglected items?

Actually 02 sensor replacement is usually more over done.
Even with a 02 sensor code many other things cause it.
To test them you need a good engine capable scanner or lab scope.
They can or may go bad but I have saw many still working good at over 200K
Give it the old good tune up and see what it does.
MT

Well I put 5 of the six spark plugs in. I will put the PITA plug in next week when I do the Throttle plate mod.

But my gosh those Autolite Platinums looked like crap after only 9 months. Lots of carbon buildup even after a dose of SeaFoam.

I will have to agree with everyone that AC Delco spark plugs are worth their money. I am going out for a test drive this evening to go buy my Dremel for the throttle mod. I will get a good mix of High-way and city so that will tell me if its that last spark plug or I possibly need to replace all my o2 sensors.

HI Cloud

According to NGK, you can use the following:

1999 CHEVROLET BLAZER TRAILBLAZER / V6 / 4.3

SPARK PLUGS
Spark PlugPart No.Stock No.Plug GapNote
G-Power Platinum TR55GP 3403 0.060
Laser PZTR5A-15 7862 0.060
Iridium IX TR55IX 7164 0.060

WIRE SETS
NotePart No.Stock No.
RC-GMX079 51081

OXYGEN SENSORS
Pre-Cat Left 21006
Pre-Cat Right 21006
Post-Cat Left 21006
Post-Cat Right 21006

AC Delco plugs are better in our engines.