I have 170,000 miles on my 2003 SLT now. I've learn some valuable lessons in the time that I've owned this car like - almost all GMC dealer service dept are complete morons and rip offs! YMMV Never buy tires from Sears or PepBoys but use tirerack.com. I love my Yokohama Geolanders!

Anyway, I was wondering what the best spark plugs are for these cars and also, what, if any, is the best thing to clean out my fuel injection system?

TIA

I do believe that the common consensus is that you should stick with OEM plugs. The AC Delco Iridiums are what will be going into my truck when the time comes. If you are doing it yourself, be sure to verify the gap on each plug before installing it, just in case.

As for cleaning out the fuel injection system, I use Lucas Fuel Injector Cleaner. I run it every 4 or 5 tanks, and I have never had any issues. I went to my mechanic for a price on a major tune, and he said all they use to clean the injectors is Lucas.

Thanks! I will have to look that up. How about Seafoam? I heard some great things about this product.

Most people run seafoam through the brake booster. Just make sure your outside when you do it. It makes a lot of smoke. You might wanna take out your throttle body and clean that. There's a "how to" at trailvoy.com, and you should probably change out the fuel filter along the frame of the driver's side of the vehicle having as many miles as you do.