Tune-Up for 99 STS

[ThreeKings06]

Just bought a 99 STS with 75,000 on the odometer, and I wanna know what to buy and replace for a complete head-to-toe tune up. I want this carr runnung like it's new. Any suggestions will be greatly appreciated

[caddydaddy]

Originally Posted by ThreeKings06

Just bought a 99 STS with 75,000 on the odometer, and I wanna know what to buy and replace for a complete head-to-toe tune up. I want this carr runnung like it's new. Any suggestions will be greatly appreciated

Congrats on the STS purchase! What color and options does it have? Mine is a black on black 2000 STS with some aftermarket parts.
For a tune-up start with spark plugs and wires. Use AC Delco parts for those. Northstar engines seem to not run as good on aftermarket parts. Next I'd clean the throttle body out.
Change the coolant, and be sure to add the GM coolant supplement tablets. It might not hurt to change the thermostat and radiator hoses now as well.
I'd inspect the belts, there are two. One main belt on the passenger side, and a small one on the drivers side that runs the water pump.
I'd also check or replace the air filter and replace the fuel filter.
You should have the brakes checked, and have the brake fluid flushed, since it does absorb some water over time and degrades after a few years with the heat. It's the most overlooked fluid in a car!

I think I got most of it there! Doing those items will make a great running and most importantly, a very reliable STS!

Good luck!

[ThreeKings06]

It's a Dark Adriatic Blue with camel tan interior. The extra's I see are all around heated seats, heated mirrors, Bose sound system (but I think they could be standard on the STS). As far as aftermarket I see the previous owner had a customised suade headliner put in. By the way what do those collant tablets do? Thanks alot for the info

[caddydaddy]

That's awesome! That dark blue color is pretty rare, I don't see many in that color. My STS has the same options, and a sunroof. I've also added a billet grille, 17" Cadillac DTS blade wheels and a Corsa cat-back exhaust system.
The coolant supplement tablets are used on all aluminum engines to seal any slight porosity problems that are found in aluminum engines. It's very important that they are added when you do change the coolant, and the coolant must be changed every 5 years or 50K miles. That is very important as well.

Take care!

[ThreeKings06]

The cat back system you added, how much did it run you and what kind of performance did it give you? What other performance upgrades are available?