I just changed the spark plugs and wires. The wires really needed to be changed, they were pretty bad. Now the car is giving a p0300 code. I'm not sure but i was told the problem is because i got Bosch plugs. Apparently blazers are picky. They're double iridium if that adds anything.

The o2 problem is that i was getting a code that one sensor was bad so i just went and changed them all. It keeps saying the one on the driver's side needs to be replaced. I don't know. Maybe the wire has a short or is damaged or something. What do you guys think? Thanks in advance.

 

First, check to make sure all the wires are on the right plugs. It's easy to confuse #1 and #3 because they don't go in the same order on the cap that they do on the engine.

I've heard that about Bosch plugs, but I don't know if I believe it. Maybe if all else fails, try some AC-Delco ones.

Which O2 sensor code are you getting, exactly?

 

The code is p0135. I don't know why I didn't type that in the first place. When I first replaced the wires I made that mistake. The car didn't crank up. After that I made sure they were in the right order. I plan to swap the plugs out again. It just sucks that the Boschs are going to waste.

 

The P0135 is for the heater circuit in the O2 sensor, which is protected by a fuse, but I don't know which one off the top of my head. And I don't know if that would give a code for only one side.

What year are you working on? I can look up the wiring diagram.

 

It's a 2004 Blazer. I wouldn't have thought it would be a fuse. I have been having problems with a short but for the interior lights.
Also my radio tends to have this problem where I have to pull the fuse in order to turn it back on sometimes after starting the car but that might just be the radio.

 

According to the diagram, there's a 20A fuse specifically for the O2 sensor heater (and presumably labeled as such). I don't have my Blazer here to confirm.

Here it is if you want to look at it.

 

I'll go take a look at that right now. That might fix that problem. I appreciate the help.

Edit/Update:
The fuse looks pretty good. Almost new. I put a test light on it to confirm and it it came on. I'm not sure what's going on there.
I still haven't pulled the plugs and re-attached them yet but they're in the right spots. I'll have to wait until the sun goes down some before
I mess with those.

 

Bummer. I was hoping it was going to be easy. Keep us updated.

 

Will do. It looks like the clouds are kind of heavy so I'll go and try to pull those plugs before it rains and take a look at the wires connecting to the o2 sensor.

update:
Changed the spark plugs, checked all of the plug wires again, top and bottom to make sure they are on both the plug and the distributor cap .
It feels somewhat better but having the same problem. I ran my scanner on it and now it's just the multiple misfires. No o2 codes, yet.
Would there be something wrong with the distributor cap and/or rotor?

 

I'm running ACDelco double irridium plugs in my 2002 ZR2. Still had the factory plugs when I changed them at 170k miles. Pretty sure the orginal plugs are platinum because that's what my Chilton repair manual calls for. AC 41-932 or equivalent. These irridium plugs on mine are about a year old now with a new set of DragonFire ignition wires and I've so far haven't had any igition problems.

Make sure your wires have a solid contact on both the plug and the distributor. It's easy to plug these in firm and the metal contact isn't seated correctly. I noticed this when I got a mild misfire on #3. You'll usually feel a click when it plugged in all the way.

Also do a quality check on the igintion wires themselves. If the insultation is broken, the power could be arcing out of the wire to any nearby metal surface or another wire. If the arc jumps to a different wire setting off a different cylinder, then that could also cause a misfire code to appear.