I had noticed a couple times that when I had the air box off, when doing other work, that two of the ignition coils were way cleaner than the other 4 ignition coils. Had obviously been replaced. I decided that I needed to get in there and check the plugs so I ordered 2 Iridium plugs, GM #41-103, and while I was in there I ordered a set of Denso Ignition coil boots and springs.
All went very smooth on the replacements except that I noticed and had to deal with 4 of the old spark plugs being very very tight to break loose. I was worried about the threads but all turned out ok. The restart was instant. I don't know if the old plugs were original but they all looked great with no deposits and all burning evenly.
I did a 2 part video at you tube about this process. If interested, have a look. About a 1/3 of the way thru the video process we had a problem and had to do 2 videos and also, the camera went landscape for the second video.
All went very smooth on the replacements except that I noticed and had to deal with 4 of the old spark plugs being very very tight to break loose. I was worried about the threads but all turned out ok. The restart was instant. I don't know if the old plugs were original but they all looked great with no deposits and all burning evenly.
I did a 2 part video at you tube about this process. If interested, have a look. About a 1/3 of the way thru the video process we had a problem and had to do 2 videos and also, the camera went landscape for the second video.