When I first got my car, it had 4k miles on it (it was a demo model), and I put Bosch 4's in it then. I finally put in new ones about a month ago at about 67k miles. Well, even before I replaced the plugs, I had just started getting cel codes, and still haven't checked them out yet. But my old Bosch 4's were in standard, used condition. Well, I took out my new ones this weekend just to check up on them, and they were black with carbon buildup. I assume this means I'm running extremely rich? Correct me if I'm wrong, but what should I look into first as far as why this happened, besides finding out what the cel means? Would bad O2 sensors, or sparkplug cables cause this? I've always used 93 octane, with no problem. What do you guys think. BTW, I put in some cheap NGK's ($1.59 a piece), cleaned my throttle body, and the car ran beautifully. The cel is still coming on either every other day, or every couple of days, and go's off after about 10 hrs.

Post your code #'s. IMO platinum 4's are not necessary(electricity finds the point of least resistance so four electrodes might be a bit much and platinum is a better conductor than whats on a standard plug)--->correct me if i'm wrong anyone.If your oxygen sensor goes then what happens is your ecm/ecu is guessing ( so you waste fuel).

Actually copper is a better conductor than platinums. The platinums just last longer because they are harder. A lotta turbo guys I talked to said that platinums are a piece of shit when it comes plugs for turbo'd engines.

Is the carbon buildup unburned gas, or gas burning too much (if theres a such thing)? Would the sensors cause this to happen. I'm going to try to go to Autozone today to get the codes. Ever since I've been on this board, and found out about the keydance trick (I've got a 98' GS), it's never worked for me.

yeah the key dance only works on 95-96 yrs

i would try using 89 or 87

once u figure your CEL codes, you will be able to diagnose your prob a lil betta..

since u mentioned fouled plugs w/carbon, its prolly one of your 02 sensors...like mentioned above...

good luck

run the ngk bkr5e-11 and dun look back ;-)

I put my +4's in almost a year ago and have not had any problems. I think i might pull them tommorow to check. As you can see in my sig, i have msd wires, Oh and i always run Premium 91/92. I'll try to get some pics if i can find a digital camera.

i foul plugs all the damn time, i can never change the damn things enough.

Keydance works on 97's also.

I believe the only year that the keydance don't work, is a 99. Which sucks incredibly for me.

Joshua47478,

Yeah, I've used Boscsh Platimum 4's since I got my car. I didn't have the problem til I got the cel, and changed to new 4's. They worked fine before the cel, but I think I'll switch to NGK's permanently anyway.

No, I'm not commenting on the key dance....

I've read post before that the platinums don't burn hot enuff. So use copper NGKs bkr5e-11s. I used platinums once and the same thing happened to me. They were fouled up in a month and the car ran sluggish. The problem was solved when I swithced to the 1 heat range hotter plugs. (Plus they were like 15 bucks cheeper too) Hope the CEL goes away. heh