There wasn't a ton of build up and it all came off fairly easy. Not sure if one of the previous garages cleaned it up when they changed the IAC (recently failed) along with a fuel system flush a couple of years ago. That's a good point about the wires. When I pulled the plugs they were NGK iridium plugs, so they were changed. I asked my grandma about it and she said someone from her church did it for her 4 years ago but wasn't sure about the wires. She has put about 15,000 miles on the car in the last 4 years according to her receipts, so I don't think the Iridium plugs need to be replaced as you can get up to 100,000 miles on them. On the other hand , the wires appear to be OEM with the factory labeling for each cylinder printed on them so they could be suspect. I will report back once I have an opportunity to change out the wires. Thanks, Rod.