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Discussion Starter #1
My 98 Seden Deville just reached 100,000 mile. Is it necessary to go to a dealer for a tune up? It costs more than $500 (I paied more than $500 for the alternator in one dealer). Or can I go to some shop for a cheap tune up?

Thanks in advance for your help.
 

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1993 Triple Black Allante
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Save yourself some $$$$ and pick up some Original equipment wires and plugs (AC Delco) and do it yourself or let someone help you do it. Piece of cake and only about $160.00 for the wires and platinum plugs.
 

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KevinK,
I would avoid both of your choices and either do it myself or find a quality mechanic to do the work.
You want a new set of plugs, probably new plug wires,new fuel filter and new air filter.
Both the dealer and quick lubes put the car on a scope and only change what is bad. The problem is at 100K your plugs are all close to bad but they will only change the ones that crossed their threshold. Do you want to keep going back every time another plug goes bad?
If you want to do it yourself let us know and we'll give you some instructions. Otherwise find a shop with a good reputation and ask them to change those specific things. Don't just ask for a tuneup without getting the specifics.
 

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Kevin:
Do what you will with plugs and wires but my originals are still doing the job at 116K miles.

I recommend (strongly) that you refresh the coolant and add the GM cooling supplement tablets or BARSLEAK Golden Seal powder. You can drain approx. 5 quarts from the radiator drain plug. Pop off the upper-most radiator hose and insert the (crushed) GM tablets or the BARSLEAK powder in the hose. Refill with premixed 50/50 Dexcool and distilled water.

Do not be persuaded to flush or power flush or whatever marketing label is used to sell a procedure that is not required. Your goal is to refresh the corrosion inhibitor additives in the Dexcool without losing control of the 50/50 mix.

Good luck...... Jim
 

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Good point on the antifreeze. I don't think of that as a tuneup item but something that should be done at a shorter interval than 100K.
I think the plugs should get changed earlier than later. Once they go bad you're loosing gas mileage and possibly doing some extra wear to your engine (gas wash of the cyl). They are too cheap to put off (especially if you do them yourself!).
 

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The plugs should be changed more often than not. Seeing as how they fire on the exhaust stroke as well as the intake stroke, they theoretically have 200k on them by 100k miles. Also, it helps prevent misfires, lost gas mileage, and reduces the risk of coil burn-out.
Take it from someone who has the headgasket issue, for the cost of flushing your cooling system, do it at least once per year. Its cheaper and easier than replacing headgaskets.
 

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My 98 DeVille has 72K miles and now its misfiring (I think)
The service Engine Light stays on and sometimes blinks and the car idles and acclerate rough at low revs.

I think its an issue with plugs and wires (not sure)

Q1) Since the service engine light is on, should I just go to the dealer in case its not the plugs and wires (they can diagnose it better....)

Q2) How much should I pay (fair price) for changing all 8 plugs and wires (at the dealer and at an independent mech)........I know some of the plugs in the back corner is tough to reach and I don't want to skin up my own hands...yes and I am lazy

Q3) Chaning just the one bad plug or wire.....is that good enough or am I gonna be in there 7 more times by the time 125K rolls by?


TX
 

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1993 Triple Black Allante
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Kevin and powergilde,

Check your codes and report them here for interpretation if you don't have a service manual. It would be advised that you pick one up if possible. O2 sensor may be a source of the check engine light, but codes should point you in the right direction.

Northstars need to have coolant checked and replaced at least once every two years and do not forget to add coolant pellets as they are so important to the life of your engine. Changing plugs and wires is not that difficult for a DIY project. Hell I did it myself and I'm not mechanic, but I do have a friend that is and he coached me while he worked on other cars. Spend a few hours and save lots of $$$$ and DIY and while your at it change the fuel filter as well. A small investment now can save you some big bucks down the road.

I hear you on being lazy, but can you afford $50 -$70/hour for the dealer to do it for you plus the cost of the parts and their mark-up. They chartge what the book says and not for the time they actually spend under the hood. If you want to get some idea then call a few GM dealers and ask what their labor rate is and what the book says time wise for these repairs. I think you will decide to DIY.

Good Luck either way!
 

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Discussion Starter #9
Hi, everyone. I really appreciate your advices.

I will try to change the plugs, wires and coolant myself. Does the PCV need to be changed also? Can someone kindly tell me how to change the fuel filter?

Thanks.
 

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The rear plugs aren't that bad. You have to remove the coils but they're only 3 bolts and you don't have to pull the wires, just move the coils out of the way.
I havn't done a Caddy fuel filter but I think the hoses screw in, as on most GM's. Someone else will have to tell you exactly where it is. The PCV is cheap so change it.
 

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Powerglide, First of all, if the SES light is flashing, it is detecting a cylinder misfire.
This can be caused by either a bad plug wire, plug, fuel injector, or combination of the three. The best thing to do is pull the codes and see what is up.
Secondly, 72K is not too early to do a tune up. You'll probably find that it helps quite a bit, especially if the car has been babied most of its life.
If youre changing the plugs and wires, get a good set of wires, and use only ACdelco plugs. From my experience with the N*, anything else is a waste of time and money, however some claim to have used decent NGK something or others that worked fine as well.
By the way, changing the plugs and wires is a fairly simple DIY job. Take your time, and you should be fine.
 

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Aurora By Olds said:
Powerglide, First of all, if the SES light is flashing, it is detecting a cylinder misfire.
This can be caused by either a bad plug wire, plug, fuel injector, or combination of the three. The best thing to do is pull the codes and see what is up.
Secondly, 72K is not too early to do a tune up. You'll probably find that it helps quite a bit, especially if the car has been babied most of its life.
If youre changing the plugs and wires, get a good set of wires, and use only ACdelco plugs. From my experience with the N*, anything else is a waste of time and money, however some claim to have used decent NGK something or others that worked fine as well.
By the way, changing the plugs and wires is a fairly simple DIY job. Take your time, and you should be fine.

Thank you guys. I have the service manuals, but no scanner to get the codes (how do you get the DTC codes? Other than to pay the dealer 1 hr labor?)



I love DIY projects and wanna do this. There's a few things detering me...

I have no tools (all on board some ship on its way here) so I have to buy sockets wrenches etc (I could use a good set so thats ok..),

living in manhattan with street parking only so I gotta do it right there curb side (i've seen people doing it...looks HARDCORE....also its cold as a mf) (or rent space in a garage....Anyone know of a space I could use in NYC?)

if I have to pay someone to get me the DTC codes......

its almost cheaper to get it done professionally after all's paid for? (or not yet?)


More fe
 

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I dont have a caddy, but an Aurora.
On the auroras, you cant use the HVAC to get codes, but I've heard 1000 times that you can on the caddys. It has something to do with pushing on and warmer buttons or something like that.
Im sure someone else can help you out here.
 

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Kevin:
I have no idea if the panel layout in your SDV is the same as a STS. But here is how to retrieve codes in a 98 STS (apologizing in advance if the SDV panel is totally different):

Key on, engine on or off (no difference)

Acknowledge any messages that appear with the INFO button

Press and hold both INFO ^ (up) plus ON/OFF buttons simultaneously

Behold Christmas tree affect

Display will read "ALL?"

Answer YES with ON/OFF button (remember this YES button)

Display will read "ALL CODES ?"

Now you have choices. One; you can respond with YES and the OBD will auto scan all possible DTCs in sequence and report them on the display faster than you can write them down. But that is OK because you can manually toggle through all the systems following the auto sequence.

Or two; use the INFO buttom to manually toggle through the system until you reach the system you are interested in at which time you can respond YES.

Go ahead and respond YES to the "ALL CODES?" display and let the OBD do its thing. The codes you are most interested in are "PCM" and they will take the form "Pxxxx"; the letter "P" followed by 4 digits.

If they go by too fast for you just, cycle the ignition switch off, and start over. Or, you can use the INFO button to manually toggle to the PCM ? display and then respond YES.

Write all the P codes down and if it was my car, I would RESET ALL CODES and drive the car for 15 or 20 minutes and run the test again to see which codes reset. The codes that are reset would get my attention first.

If you are doing this at curbside, I urge you to be sure the headlights and all interior lights are off. This can take quite a while and if your battery is marginal.... You can picture the rest!

Good Luck with it. Many places on the web to decipher the DTCs including

http://209.145.176.7/~090/awh/dtcobd2.html

Jim
 

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Powerglide,

Just missed you as I was in NYC(Manhattan) last week for Thanksgiving. I would have been glad to help you out. No plans to return anytime soon, but we would be glad to help coach you thru this. If you have a service manual, then read up on how to access the codes for your ride in there. You have been given good info here and its not that hard a DIY project, except we can't control the weather.

Good Luck
 

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I don't know what auto part chains are in NYC but Checker,Pep Boys,and Auto Zone all have tool sets for $20-30 that will cover spark plug change. Sears will have a better set but maybe a little more money.
You should be able to change plugs and wires in 1-2 hours yourself.
Make sure you get some antisieze and use a small amount on the spark plug threads. This will make the plugs tighten easier so be careful not to overtighten. It will also protect the threads in the aluminum heads.
 

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Thanks everyone for all the support.

I will go pull the codes myself to see whats up.

Reporting back soon!
 

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Can someone tell me how to get DTC codes from my 98 Deville?
JimD's method not the same for Devilles...I tried.
Thank you
 

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I am interested in doing a tune up on my STS. Does anyone know where i might be able to find step by step instructions on how to do it. I am not the sharpest tool in the shed but definitely not the dullest. Any help would be greatly appreciated.
 

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powerglide said:
Can someone tell me how to get DTC codes from my 98 Deville?
JimD's method not the same for Devilles...I tried.
Thank you
alright...Ii fgured out how to get the codes.

Its showing a p0300 (i posted another thread) and again after reset.

Hearing advice to run WOT in 2nd gear up to 70+ MPH to blow out the crap....any suggestions?
 
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