View Full Version : 03 DTS Major Tune Up

02-17-06, 10:19 PM
Vehicle started idling rough after no probs. Took to dealer, they claimed major tune up necessary (70,K miles). $1300. I asked what codes they claimed coil pack, crank sensor, #7 misfire. Asked what $1300 bought - was told - coil pack, crank sensor, wires, plugs, fuel filter, air filter. Feel as I'm getting hosed, any help by the group would be helpful.

02-17-06, 10:59 PM
Vehicle started idling rough after no probs. Took to dealer, they claimed major tune up necessary (70,K miles). $1300. I asked what codes they claimed coil pack, crank sensor, #7 misfire. Asked what $1300 bought - was told - coil pack, crank sensor, wires, plugs, fuel filter, air filter. Feel as I'm getting hosed, any help by the group would be helpful.

What codes were set?

There is no coil pack; there are individual coils.

There are no plug wires; the coil connects directly to the plug.

Fuel filter might cause a high RPM / high load problem; not at idle.

Air filter; higher RPM also.

Faulty crankshaft position sensor typically causes random stalling.

#7 misfire; now that might be a fouled plug or a faulty coil.

What codes were set?

Find a dealer that will do a proper diagnosis. Or pull the codes yourself.

02-18-06, 12:38 AM
Just came back from dlr, car started idling rough out of blue, dlr claimed it needs major tune up, coil packs, crank sensor, plugs, wires, air fuel filters $1300. 70K miles on car. I think I'm getting hosed, any help would be great.

You are definitely being hosed.

These engines do not require a "major tune-up" too often.

* Coil Packs are not a maintenance or tune-up item. They work or don't work (usually).

* Cranks sensor have been known to go back in certain years, but that usually results in a stall, not a rough idle (correct me if I'm wrong anyone).

* Spark plugs in these engines (Double Platinum) are designed to run 100k miles (many have gone far beyond that just fine)

* Spark plug wires are technically supposed to last the life of the vehicle, but they definitely do go back every now and then. Some people do like to include them in a tune-up, though.

* And of course, Air/Fuel filters are both variables. You need them or you donít.

I say you tell the dealer to go to rot in hell. They need to tell you what is the problem, or you should go elsewhere. Either go to another dealer, or a reputable independent shop. Don't let those idiots rape you.

02-18-06, 04:30 AM
Unfortunately that sounds about right for dealer rates for parts and labor. The plugs would've needed changed at 100k anyway, so you're a little early. Air filter and fuel filter are cheap and you might've been due. It shouldn't have needed crankshaft position sensors - they're redesigned and pretty much trouble free from '02 up.

The coil packs are in 2 'cartridges' - 4 coils per cartridge; one on each cylinder head. You have to replace the 'cartridge', not a single coil. I think they're around $300 per side. My car had a nasty misfire that I narrowed down to the coils on one bank of cylinders. That's probably all it was in your case. Actually I'm pretty sure my misfire was the result of corrosion between the coils and the plugs, not the coils themselves but I let the dealer replace the cartridge anyway. There are no plug wires.

Sounds like rather than properly diagnose it they just replaced everything that might cause a misfire. All of those things could cause a misfire, but it's not likely they all went bad at once.


02-18-06, 12:12 PM
Don't let those idiots rape you.


obtain shop manual, do work yourself. if this is not feasible, please do find a trusted dealer that won't rape you 6 ways to tokyo.

usually between a shop manual, this forum, and a friend with tools you can accomplish much. we're always willing to help.

02-18-06, 02:30 PM
appreciate the reply, do you think this work above the head of local mechanic who service my 01 and 02 suburbans? Any info on the crank sensor? I think there are 2, not sure. Thx

02-18-06, 04:27 PM
If you go back there, bend over and grab your ankles. I'd R & R the plugs..... myself.

02-18-06, 05:57 PM
any suggestion on whre to get coil cartridges and crank sensors? have not located any online. thx

02-18-06, 06:06 PM
before you start throwing parts at it...is it throwing any codes?

find out how to throw the DIC (instrument cluster) into diagnostic mode. this will flash any current and any stores codes in the PCM. this will give you a head start...copy down any and all codes and report back. someone will be more than happy to tell you what they mean

02-19-06, 02:27 AM
2003 has no plug wires. It's coil on plug.

Seriously, I would change the plugs at 100K, I do fuel filters at 50K myself, though many do not do that with good results, so you might do yours at 100K, do the air filter when it's dirty, usually around every 10-20k.

02-19-06, 07:19 AM
any suggestion on whre to get coil cartridges and crank sensors? have not located any online. thx

I was under the impression that you had this work done already. If not, there's time to properly diagnose it. If it's really running rough it will throw a P0300 code indicating a misfire. You probably have a P0300 code stored if the dealer was able to run the misfire diagnostics and narrow it down to the #7 cylinder.

The crank sensors were an issue through the 2001 model year. The 2002+ have redesigned sensors that supposedly won't fail the way the eariler ones did. There are 2 crank sensors an "A" and a "B". They will throw their own codes if they go bad, sometimes in conjunction with the P0300. When they fail the car will take longer to crank and it will stall at random. IIRC, they don't usually cause a rough idle. Given their function, though, it's theoretically possible that they could (which is why there is a crankshaft re-learn procedure when you replace them). If you have a rough idle I'd look elsewhere for now - I'd focus on the coil packs and/or plugs.

The cartridges can be purchased from www.gmpartsdirect.com. The rear one is part number 1104075, the front is 1104076. They're $142 each plus 'shippng and handling'. Their prices are really good, their shipping costs are really high but when you net the 2 together you still come out way ahead of most dealers unless they're giving you 'garage' pricing.

The cartridges are fairly easy to remove, the front one (as you face the engine) is easier than the rear. To get the rear one out you have to remove one of the AIR pump solenoids and it's tough to get your hands or tools in there. You have to remove the coil cartridges to change the plugs anyway. I would consult a factory service manual or alldatadiy.com. If you decide to do it yourself, look for carbon tracing and/or corrosion where the coils meet the plugs. If the stealer has narrowed it down to the #7 cylinder then you're looking for problems with the cylinder at the back right corner of the engine (as you're facing it).


02-19-06, 10:16 AM
I know what you are going through, 2 weeks ago I accidentially ran out of Gas on the freeway! That's when my normally quiet and powerful 300 HP Northstar started acting up.

I called my SoCal Dealer, he quoted $875, for a complete tune-up. My car has 109500 miles on it. So I already knew that it was overdue for the 100K service.

Here's what years of auto repair taught me, don't go to a dealer unless you have collision damage or warranty repair! Because of a dealers investment in property, inventory parts, automobiles, and personnel they can't afford to give you good prices--their overhead is simply too high.

I took my car to a local Tune Up Masters, whom I interviewed over the telephone to determine if he had worked on the Northstar V8 before. He informed me that Northstar tune-ups on Cadillacs and Oldsmobile Auroras, required Factory 100K Platinum Plugs, but before he'd do the work they would run a OBIII diagnostic to determine the reason the car wasn't performing properly. He quote me the Tune-up only price of $130., the diagnostic costs $60.00.

Thursday 02/16 I had the tests done and it indicated a problem in cylinders 3, and 4. The technician removed both plugs and examined them, both appeared "Worn Out", he changed them with Normal plugs and RETESTED. The problem was gone, and the diagnostic indicated proper firing.

Because of the mileage I agreed to a complete Tune Up and also a change of the Fuel Filter (I told him about the Out of Gas incident), the tech recommended the filter change as he said the filter protects the fuel injectors ($35.00 filter cost). He said the reason he tried the spark plug test first was to eliminate fuel system concerns.

Well the car is running great, fuel efficent and Northstar Fast! The Final Bill $243.00 w/Factory Parts Platinum Professional Plugs w/ 100k warranty. It helped that day I was talking to a friend, who owns 5 cars and does rebuilding he recommended also that I consult businesses that deal with Tune, Speed Shops, and Smog REPAIRING. He indicated because of their lower overhead, and because of their familiarity with engines, emission, and fuel systems they are better able to get to the problem.

I know this post is long, but I hope this helps. Let us know how everything turns out.:bouncy:

02-20-06, 08:24 PM
All the replys are great, pulled the car from the dealer, Now on to plan B.
Couple of additional questions
1) How difficult is it to replace rear coil cartridge? any special tools needed?
2) Crank Sensors, how difficult to get at? what is the "Re-learning process"?
3) Any thoughts about doing the cam sensor while apart?
4) any other parts I should look while contemplating work?

Not sure of plan but gathering information. Once again thanks for info.

02-21-06, 02:11 PM
I would simply remove all eight plugs and look at them carefully. If one cylinder is misfiring heavily it should show on the plugs. The plugs will basically run forever unless something happens. Possibly the platinum pad came off the ground electrode or the center electrode and the gap has worn?? If the misfiring plug looks Ok I would still replace it before proceding with the coil pack on that side.

It could be the crank sensors but the 03 crank sensors were pretty robust. Usually a crank sensor problem manifests itself as a no start or a random stall....not just a rough idle. Could be but wouldn't be my first guess.

The other thing that could happen is an injector sticking or dripping on one cylinder causing a rough idle and misfire. If the plug looks heavily fouled and/or wet with fuel after idling and misfiring then I would tend to suspect the injector maybe. You could lift the fuel rail up and turn on the key to pressurize the fuel pump (don't crank or start) and watch the injector tip for dripping to see if there is an obvious injector problem.

There is no $1300 "major tune up" required. You have a specific problem that needs proper diagnosis and repair.....not a "tuneup" or someone to throw parts at it.....

You might approach the dealer service department with the idea that the car is certified for emissions performance for 100K and that it will clearly not pass emissions idling that way...so it should be diagnosed and repaired under warranty..... "Tuneups" are just not required nor necessary. Besides, there is nothing to "tune up". If a plug has failed or a coil has failed or an injector has failed then it needs to be diagnosed and repaired. No such thing as a generic tuneup.

02-21-06, 07:01 PM
I would start with the plugs. I highly doubt it's the crank or cam sensors. If it ain't broke, don't fix it.

The #7 cylinder is in the back right corner. You don't need any special tools, just whatever size you need to get the top cover off, a 10mm socket for the coil cartridge bolts and a 10mm wrench for the AIR solenoid (nuts are on the bottom - tough to see and tough to get at).


STS 310
02-21-06, 07:28 PM
The dealer is doing exactly what their supposed to do, the barrage approach.
Replace everything involved with the "problem".

Nothing surgical about it. As in war time (pre-Gulf War), why wonder what house the bad guy is in when you can destroy the entire town!