New Spark Plugs

[tblake]

Hi guys,

Yesterday I put a new set of NGK Iridium TR6IX Plugs in the GTP. I gapped them to .050" and so far everything seems good.

My question is... The 6 I took out were autolite ap605's. They were installed last year right around this same time. Probably almost exactly a year ago. All of them came out and looked pretty good (worn out, but good), well, all of them except for one. Number 6 came out and had this brown/blackish residue on the ground electrode and some on the ceramic insulator and it smelled a little like gas.

I tried to get a picture, but my camera's autofocus wasnt cooperating. This is the best I could do.... On one of them you can sort of see the black marks on the ceramic insulator for number 6.

What do you guys think? There are no drivability issues, the car does sort of have a slight miss now and then in park at idle, but its been like that since I owned it. Good accelleration and no missfire ses DTC's are set. I did recently run a bottle of chevron fuel injector cleaner through after my LIM gasket change, which might be why the other plugs have sort of a grey color to them.

What I think I'll do is hook up my laptop and digimoto and monitor missfire data for a drive or two and also remove that new plug a couple times in the next couple weeks to see how it looks.

I'm sort of thinking I have a sticking injector. What does everyone else think? Sorry for the book! Here are the pictures.

[tblake]

Today on my way home the SES light turned on.

When I was able to scan it at a red light it came up with P0138.

O2 Sensor Voltage High. Does this mean my O2 sensor is shot, or does it mean that the voltage is high due to the motor running rich because of a bad fuel injector?

Please advise guys! Thanks!

[GTP Dad]

Plug 6 may indicate a leaking injector. As for the sensor the additional fuel may be the cause of the issue. I would reset it after changing the plugs and see if the light comes back on. If it does change the sensor and see what happens. It is quite possible that the additional fuel has damaged the sensor or that the sensor is carboned up due to the incomplete combustion from the excess fuel. You may also want to change the front sensor as it controls fuel going into the engine and It could be slow and causing too much fuel being injected into the engine.

[tblake]

Thats what I dont understand. I have a ZZP O2 emulator for the rear sensor.

Number 6 when removed was pretty dark/wet with some built up on it.

When I got home tonight, my car seemed to be missfiring at idle.

Since I knew the injector was flaky, I replaced it with another one that I had in my tool box and I cleared the SES light. So far it seems ok. I'll drive it for a little while
and see how it goes.

Here is a snapshot of the datastream when the DTC was set.

Click Here