Your C5 ignition system longevity

Yellowshark

Well-known user
Hi, well we know that the stated service interval for the spark plugs is 100,000 miles, although I use Denso IT16TT iridium plugs and change then at 60,000, Most people change the leads at the same time as you are bound to destroy a couple of leads when you remove them. But what about the coils? Well at 19 years and 159,000 miles I have just replaced a defective coil which was causing the car to backfire and took some time to isolate, many thanks to my brand new OBD2 scanner for that. I will be saving up to buy another 7 coils as I presume they will all start to fail in perhaps[s not the distant future, not something I want to happen during a trip aroud France, whenever.
 

Yellowshark

Well-known user
Weeeell, a true story - before I changed the coil I fitted new plugs and leads to the passenger side bank. What a sh+tty job, but the lead on cylinder 8 came off really easily and on removing the plug I found it to be looking brand new. So 7 years and 40,000 miles and I had not noticed I was firing on 7 cylinders only.
 
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