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60K Service - Coils

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'O4 C2 and I will be replacing the coils most likely with the plugs. I assume the coils are Bosch and I am interested to know if anything other than OEM Porsche parts should/ can be used (maybe Audi coils fit?)

Trying to save $. Thx for replies.

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'O4 C2 and I will be replacing the coils most likely with the plugs. I assume the coils are Bosch and I am interested to know if anything other than OEM Porsche parts should/ can be used (maybe Audi coils fit?)

Trying to save $. Thx for replies.

If you are trying to save money, why not just leave the coils in it until they act up.

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When I did coils I found the Beru ones from Vertex to be the best price. I would recommend doing them now. I didn't do mine, then 1.5 years later I had to have them replaced because they started to misfire. I drive year round in Wisconsin, and I can tell you that replacing coils in Feb in a garage that dates from 1923 is not the most fun you can have working on your car. It would have been way less stressful to do them with the plugs. Don't know if you store it for the winter, but I see you're from Wausau.

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Thx JFP & Dk570, thinking about the coils as I think I detect a slight miss when parked and running. No codes are thrown, but figure while I am doing plugs might be the best time to change the coils on a 10 yr old car. Make sense? Am I correct that w/o software there is no way to know which coil or plug may be bad?

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There is a simple test for the coils to see if they are good or not. All you need is an ohm meter.


Resistance between terminal 1 and terminal 15 at 20°C: 0.3 - 0.7 ohms.

Anything outside of this range is suspect.

Likewise on the spark plug connectors:

Resistance: approx. 2 k ohms

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looking for some sage advice. 03 C2 with a CEL. recently purchased. ppi was totally clean. 4 weeks after getting car cel light code is p 0420- cat bank 1. ran code at local auto parts store. take car to local independent. He claims that there are also 2 other codes- p 0301 and p 0301- which did not appear when auto parts store checked codes. he suggests replacing 6 coils and spark plugs which may clear 0420 code. mechanic who did ppi said he has replaced one coil in 6 years and doubts this is this cause. he is suspicious of new mechanic. any ideas what could be behind this. Could bad cat cause engine misfires? could bad oxygen sensors be cause? also new mechanic says radiator expansion tank leaking- even though i have not seen one ounce of coolant in my garage. not sure if new mechanic is taking me for a ride.

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From what you describe and the codes P0301, P0420 your new mechanic has put up a red flag in my book. Just because you have these codes does not mean you throw parts at them. I would first have to prove to myself that all of your coils were bad before I could recommend replacing any of them. And I can see your being setup next for a CAT with a P0420. If I were you I would run far and fast from your new mechanic! I dont know the laws in NY but in California if you start recommending this kind of work you better be right. The CA Bureau of Automotive Repair comes down big time on guys like this with a big fine and then pulling your license.

Edited by binger
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  • 4 months later...

Just got a p0301 on the way home tonight. The car sounded a little rough on start up, and stuttered under moderate acceleration after it warmed up and threw a CEL. Idle was definitely rough after I got off the interstate.

Car just hit 60k miles and I have been planning to do plugs/coil packs, I am second owner (got it with 32k) and I am assuming plugs are original.

I live in Florida and it has been a monsoon here all week, so I am hoping it is a moisture/cracked coil pack issue. I'm going to put the car up on jack stands and see how coil pack 1 looks tomorrow. Anything else you guys would suggest looking at while it is up in the air?

Obviously still looking at doing the plugs/coils in the very near future, but if I can get it running smooth (and keep it out of the dealer's hands) until then it would be great.

(Cylinder 1 is the drivers side furthest to the rear on a US 996 correct?)

Edited by tampa996
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