I just installed some NGK TR-55's to replace my stock platinum plugs. Everything looked good, nice healthy color, until I got to cylinder number four. For some reason, the lil' platinum thingy that comes from the end of the side electrode was very short, almost missing. My engine hasn't set any lights about the ignition system, misfires and such. Just curious if anyone has seen this before and if so, what it means.

 

How many miles did you have on the plugs that you removed?

 

Only 53,000. All the other plugs were good, electrode in place and all were still gapped just right. Funny thing is, the engine never gave any sign of being weak on one cylinder.