I have a 99 cat. I was thinking about changing out my spark plugs. I have a lot of experience working on my old Acura Integra, but I see that engine is nothing like my cat's. I also got the service manual. I just bought the car a month ago and it has about 60,000 miles on it. The questions I am asking are:

1) How difficult is it to change the spark plugs, should I leave it to the professionals?

2) What is the recommended intervals to change spark plugs?

Thanks.

I would like to know this also and know if anyone has used the e3 plugs or any upgrade spark plugs and what difference it made :stirpot: www.jcwhitney.com has a few different ones for the catera

I've changed my plugs. I put in Bosch 4+ Platinum. They work just fine. And yes, I did notice the difference, since my old ones had oil all over them and little letters saying "GM" :)) The hardest part is getting to the plugs closest to the cabin, and those on the driver's side need some stuff taken off the engine before you can get to them. But having the right tools and some patience is all that you'll need. It was my first time and it took me a bit more than an hour. Not sure about the interval, but my Cat had 100k on it. I think 60k should be the right time.
Good Luck! ;)

thanks r-caddy