Plug Change Now P0430 and a couple theories

[backroads]

I finally got around to changing the plugs on my 2006 4.6 v8 Limited,95000 miles. So my plan was to go for it, and if a plug broke I would just order the Lisle tool and let the plugs absorb more PB Blaster for a few days. So I loosened all the plugs 1/4 turn and sprayed PB down the holes and let them soak for 24 hours. The Pb Blaster level never went down so I loosened them another 1/8 and left them for a couple hours.
Then using an impact driver I remove #1 and sure enough it broke. So I ordered the Lisle tool and 3 days later I removed the rest of the plugs. 4 of them broke, and the Lisle tool did its job and an hour later I was done, fired up the motor, ran fine and there was smoke from whatever PB Blaster was in there even after cranking it over before installing the new plugs to blow out excess PB.
My theory about the broken plugs is that they usually break when you first crack the plugs 1/4 because 1/4 turn is enough to break the plug below the threads.
Then after about 25 miles the cel comes on and its P0430, my theory as to why that happened is because PB Blaster may have contaminated the cat, or an 02 sensor.I cleared the code twice but it comes back after a while.
Thoughts guys?
Thanks
BRoads

 

[V8SHO]

I would get a temperature reading of the exhaust at the inlet and outlet of the catalytic converter to get an idea of its efficiency. An exhaust temperature reading higher at the inlet than the outlet indicates the catalytic converter is no longer working efficiently. Probably the 02 sensor reported a rich exhaust due to the PB blaster and triggered the code. The test above will prove in or out a catalytic converter problem.

 

[suzook]

I would have just left the plugs. Plugs in modern vehicles can easily go 200k miles.

 

[BrianDye]

No...do not leave these plugs for 200k miles.

In another year or so when my 06 is paid off, its going to be a weekend toy, and I want to find a V8 4th gen. These stories are terrible to read though. How hard was that tool to get the plug(s) out once they broke?

 

[Tech By Trade]

I would have just left the plugs. Plugs in modern vehicles can easily go 200k miles.

Not on the POS V8. You are asking for big problems. Father inlaw just had his changed in his F150, ended up costing him 900 bills just for the plugs. 2 broke off.

Best bet is to get yourself a decent code reader. it should be able to show you the voltages on the o2 sensors in live mode. That should be able to tell you which one is flaky if thats the problem.

 

[BrianDye]

The Ultra-Gauge is a nifty little tool to have. I lent mine to a friend months ago and haven't seen him since, so I cant check and see if it reads that, but it had pages upon pages of data it can read. I think I paid about $60 for it, give or take $10.

 

[backroads]

No...do not leave these plugs for 200k miles.

In another year or so when my 06 is paid off, its going to be a weekend toy, and I want to find a V8 4th gen. These stories are terrible to read though. How hard was that tool to get the plug(s) out once they broke?

The Lisle tool is pretty easy and quick to use

 

[backroads]

Not on the POS V8. You are asking for big problems. Father inlaw just had his changed in his F150, ended up costing him 900 bills just for the plugs. 2 broke off.

Best bet is to get yourself a decent code reader. it should be able to show you the voltages on the o2 sensors in live mode. That should be able to tell you which one is flaky if thats the problem.

I have scan tool I'll read that tonight. I think they are both reading the same I'll post results and the fix for this problem when I get it figured out. I think it's the cat on bank 2

 

[backroads]

Checked the o2 sensors with my scan tool. All 4 are fluctuating between 100-800 Mv which means both cats are bad. I'm wondering how they could both go bad after a plug change? only thing I can think of is that they got coated by PB blaster at startup. It runs fine, shouldn't affect driveability. Goung to get a heat gun and verify. Also selling my used Lisle tool $30.00.
Thx
Backroads

 

[4D X]

Wouldn't it make more sense that the 02 sensors themselves maybe have some burn off coated on them? Clean the sensors.

 

[backroads]

Just checked the temp on the cats and they're functioning correctly, around 150+ degrees hotter on the outlet compared to the inlet. And the o2 sensors are showing the correct voltage. Cancelled the trouble code and it hasn't come back after 20 miles. Hopefully it has cleared itself up. If it does could it be because of an exhaust manifold leak? Which I'm going to tackle next. Then the front left hub bearing.

 

[V8SHO]

Glad to hear the catalytic converter is functioning well. That means the PB blaster going through the engine caused a temporary rich exhaust and triggered the code.

Even if the code were to reappear (it probably won't), you know the catalytic converter is operating properly due to the higher temperature at the outlet.

I suppose that an exhaust leak before 02 sensor could result in a lean exhaust which the PCM could compensate by adding fuel. But if the 02 sensor is switching properly and fuel trims are normal, then it shouldn't be an issue.

 

[backroads]

cel came back on