90,000 Mile Service--Should I replace ignition coils?

I've decided to do most of my own 90K mile service on my 04 C4S cab.--plugs, fluids, and filters--everything but the brake service, which I'll leave for my shop and an experienced mechanic. Here's the question I'm fretting over: since I will be changing out the spark plugs, doesn't it also make sense to change out the plug tubes and the ignition coils while I'm down there? Is it worth the money to do so? The plug tubes are cheap, so that's a no-brainer. But, the ignition coils can be rather pricey--upwards of $200. I have no reason to expect that anything is wrong with the ignition coils. But, I believe they are the original coils from the factory. The only reason I'm looking at changing them out is the now-advanced mileage on the car. My engine runs fine, gas mileage is what's expected, and there are no codes being triggered (last inspected two months ago). Should I just go ahead and lay out the money for the coils now while I'm down there? That said, I have other less pressing items of a purely aesthetic nature I'd rather spend my car budget on--buffing the paint, new rims, door and windshield decals, etc. They can wait, but should they? The extra $200 could make a difference there. Any advice would be welcome.

I would replace them, they are known to fail long before 90K miles and you will hate the misfires. You're already going to have them removed. The new coils are a 997 part number, make sure you get the new hardware (two screws each) with them. Good luck!

Why replace good parts? Its a 90k mi car. Drive it.

I agree with 996AE. My 996 just turned over 90k miles on Wednesday. I plan on doing a major service in July when I have some time off. I will inspect the coil packs. If they look good and test good (there are some specs using an ohm meter, as I recall), I will continue to use them. They are not that hard to get to if you do have one fail.

I guess it depends on your budget, but I'd replace them. It's easy to do while you're replacing plugs, and at 13 years and 90k I'd be surprised if one or two aren't on their way out. A couple of mine were cracked at 63k ... not a problem in dry weather, but once it rained I realized something was up. BTW, your car doesn't have spark plug tubes. 996.1 does, 996.2 does not. So you save a few bucks there.

It's no easier to replace them now or if an issue pops up. There simple to swap. Run what you have.

Change everything you can...plugs, coils, belts, inspect all the wiring. All that rubber and plastic has been through a lot of heat cycles. Don't treat your 911 like you were a used car dealer and it was just something you wanted to flip.

I just replaced my plugs and coils along with other items for my 90K service. The engine pickup (which I thought was originally very good) or response was amazing afterwards. The 90K service is the first real biggy in my estimation. Hey suit yourself but I say 'yes' to changing the coils. BTW no cracks in my old ones. I found it easier to remove the cats before doing the plugs and coils.

I am certainly not an expert on the 996 line as I have had mine about 18 months but from what I have read, a couple of them are a pain to get to. If are are going to drop your engine to do the work then I would definitely do the coils. Even if you are not dropping the engine I would replace them since you are there anyway. I have 88k on my p-car (same as yours btw) and will have the shop replace the coils,, mounts and probably the AOS when I have the IMS done.

I would replace them only if you will regret having to go back in there and replace them when/if they fail. Do you have the time and energy to? If yes, take the gamble and don't replace them. Otherwise, getnin there and do it while you're there. A quick note on failure items versus maintenance items: a lot of people think that items on these cars should be replaced proactively. I have an original water pump, original IMS, original AOS, original RMS, original clutch on my 18-yr-old car. While I know that common repair items are just that - common - I also know that most things don't fail. So replacing a part that's known to fail 10% of the time to me doesn't make sense. Oil, filters, brake fluid, wipers, tires, pads, spark plugs - on the other hand - will wear out 100% of the time. Proactive replacement of such items might make sense depending on where they are in thier life cycle. Generally speaking, most things on these cars are highly engineered. Which means some parts can last 50 years. I have a 1983 IBM computer with a hard drive. Hard drives are known to fail, especially after 5 years. Yet this 35-yr-old hard drive is still humming along. Do what you want, but know that 9 times out of 10, the cost to replace items on your Porsche are mostly labor-related. Parts are expensive, but most basic repairs and maintenance coat $80-$130/hr of a mechanic to perform. Not that someone less qualified cannot do it, but that's the rate range of Porsche/German mechanics. If you have the time, spend it on your car where you can and try to let the parts live up a long life.

Assuming all the coils are working "fine" (I.e. No misfires) then pull them out, and if they're cracked, replace them (they will fail sooner rather than later if they're cracked). If not, put them back in and drive the car. Star figuring out some sort of maintenance allocation, so when it is time to replace them you're not surprised financially.

Well here is a vote for "while you're in there replace them all". Just did all mine at once. The newer coils are upgraded and better. Car just seems to be much happier and run better. I had a misfire on #6 after car wash, so cracked coil. I did not want to just replace one and have to keep records for which one has been replaced and so on. It's a Porsche! Don't go all cheap on it.......

Well, you asked advice, you got it! :-) A great 360 degree of advice. Interesting username, that must be an interesting story! Pics always welcome of your mount btw. Volkert

Maybe it's a little off topic, but if you can do all of this other work, then you are more than capable to do the brake work, too. Brakes are probably the easiest item on the list to work on. It pisses me off when I get an unsolicited quote for brake repairs on a car when it is in for other service because the prices are normally ridiculous. I think people are scared to do the work themselves, so they will pay a lot to have a professional fix brakes. But, they ain't rocket science.

I started getting a misfire at 60K, and I replaced all 6. Car is much happier. As kcattorney said above, if you can do all these other work then you are more than capable of doing the brake work, too. That should save you some money, money you can apply to replacing the coils.

Absent any misfire issues and provided the coils look ok when you remove them -- be sure you handle the coils with care! -- to replace the plugs my recommendation would be to leave the coils in service. IOWs, don't fix it if it ain't broke. 'course, if you do not change the coils there is a slight chance one could go bad and you might have to go back in there and then replace the coils. There is also the chance a new coil could suffer from "infant death" and you would have to go back in and replace just the bad coil, too. But if the coils look ok chances are they're ok to "reuse". Have to add though cars driven in inclement weather a lot appear to suffer from accelerated coil deterioration. If you use your car year 'round and in the winter the car gets exposed to snow and salt then premature replacement of the coils might be called for. Also, I have to add coils can be rather long lived. Original coils in my Boxster have lasted over 310K miles. There have been just two times the engine has misfired and this at cold (and damp) start. It has never misfired at any other time. When the plugs were changed I mentioned this misfire to the tech and he paid particular attention to the condition of the coils and said they all looked just find and didn't see any reason to replace them. That was over 5 years ago and the coils have remained trouble free ever since. However, even though the original coils are apparently just fine I might -- might -- elect to replace the coils regardless come the next spark plug service just to see if new coils make any difference in how the engine runs. (Right now it is running pretty darn good, believe it or not.) New plugs have not made a difference in how the Boxster engine runs or how the 996 Turbo engine runs. But a while back -- at around the 140K mile mark -- I had both plugs and coils changed in the Turbo -- the plugs had around 10K miles left before they were due to be changed on miles -- and the engine ran better after. Since I have had the plugs changed before in this engine with no improvement I attributed the improvement to the coils.

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^This. Just did a major service on a new to me '01 986 with only 40K miles. Coils and other plastics age out. I much prefer doing this now "with my sleeves rolled up" and then not worrying for the next 5 years. BTW, I took advantage of a sale Design911 was having on the 997 coils, and thanks to the exchange rate it was cheaper to buy them from England and have them shipped than any local option. The new coils are a much beefier design, and include the new hardware to install them. T

Google 'bathtub failure curve'. You are just as likely to put a marginal 'new' part in. Coils are solid state device. They have no moving parts, and would not be considered a wear item like plugs. Clean, inspect for cracks, measure resistance, if no condition faults, install and drive on. Save the bucks for real issues, don't make things up as you go.