What is the difference between the two types of tune ups. I was thinking of doing my own (buying a shop manual and all that) but I wasn't sure if it would tell me the difference.

Also, is it best to take it to dealer so they can charge me an arm and a leg ($500+) or is it simple enough to do on my own?

Oh, one more thing, where can I get a shop manual for a 98 STS cheap?

Thanks a million!

Go with the factory shop manual. It consists of three manuals for 1998. They're always on eBay and that's where you'll find them the cheapest.

As for the tune-up, you'll have to ask your dealer what their's consists of since the content varies from dealer to dealer. A lot of them tack on snake oils and other odds and ends.

If you're handy do it yourself. It doesn't get any cheaper than that and at least you know what you did.

There are several threads that gave info and opinions on major/minor tuneups.
A dealer or shop probably won't give you new plugs or wires unless they are bad. If you do it yourself you get a whole set!
Plugs, fuel filter, air cleaner for sure. Plug wires would be a good idea.
If you havn't changed coolant in a while you might do that but it really isn't part of a tuneup.

http://cadillacforums.com/forums/showthread.php?t=6273

http://cadillacforums.com/forums/showthread.php?t=5503

Its all easy stuff, replace the plugs, wires, fuel fitler, air filter, clean the MAF with brake parts cleaner..... I suppose the next step up would be to change coolant, ATF, other fluids, Tstat, etc.....

Thanks for all the info peoples!! I have to get all the supplies necessary to make the changes. I am going to change my wires, plugs, coil packs, oil filter, oil, air filter and maybe a coolant flush. I am also thinking about changing the fuel filter.

I am still trying to find a factory manuel on ebay. I found one at another website for $75. It says it is a service manual, but I heard there is a differnce between the two and the factory is better. So I am still looking.

By the way, since I am not extremely knowledgeable at changing parts and what-not, what is the MAF, ATF, and Tstat? I know it's a dumb question to all the professors in the forum, so forgive me in advance for asking a stupid question.

Thanks all!

MAF- Mass air flow sensor, detects amount of incoming air..... Its on the intake tract and looks like a box with a connector on it....

ATF- automatic transmission fluid

Tstat- thermostat..... Helps engine heat up faster, and regulates coolant flow to keep engine at optimum temp....

BTW..... the manuals at www.helminc.com ARE the factory service manuals....

MAF is mass air flow meter
ATF is auto trans fluid
Tstat is thermostat

The Caddy manual is 3 volumes. $75 is probably for the right one. There is a big price range used vs new. Sometimes you get lucky and get them cheap.

Just out of my curiosity...

I don't know anything about NS engines, so it is just for my
infomation (some day I may be rich enough to buy NS cars!).

Anyway, changing coil packs is in Jetillac's list. Are coil packs
supposed to be changed regularly? I thought they are something
that never wear out.

Got me. Just like spraying the Mass airflow sensor with brake cleaner. Maybe on the older potentiometer MAFs used on other makes of cars, or maybe Wes meant throttle body. (Gasp! Did I spot a BRAINFART! :canttalk: )

Every now and then I get a real rough idle and it lasts for a while then goes out. It's almost like there is a misfire. I was searching the forum and came across another thread were someone had the same issue. They said they changed the coil packs one by one until they found the bad one. At that point it purred like a kitten. I figured I would at least give it a try.

Every now and then I get a real rough idle and it lasts for a while then goes out. It's almost like there is a misfire. I was searching the forum and came across another thread were someone had the same issue. They said they changed the coil packs one by one until they found the bad one. At that point it purred like a kitten. I figured I would at least give it a try.
Sorry dave you didnt spot a brain fart.... The "old" type of MAF (hot wire type, not sure what that thing was you said) can benefit greatly from a cleaning.... It is less accurate at low flow rates (idle) to be more accurate at high flow rates (WOT).... As it gets gunked up it becomes less accurate at readings at idle, thus making the idle not as good.... PLus you clean the MAF screen too!

I wouldn't use brake cleaner though. Electronics cleaner perhaps. The Gm style is not as suseptible to crud buildup as the Ford style is though.

Brake/electrics parts cleaner is what I use... I got some at NAPA.....

Although the designs used on GM and Ford cars is probably much different then the Jap design I have....

Thats more of what I was getting at. Does your car use a trap door? Thats connected to a potentiometer, which varies the resistance the wider the door opens.

Dave.. Mine is very similar to the 96+ MAF.... Just the hot wire element and the screen in front of it.....