After some pretty serious misfiring/bucking after about 45 minutes at idle (for reasons too long to explain), I've realized I'm likely due for new coils and plugs (It has just over 200K on it and I'm not sure of the overall history of the vehicle as I purchased a few months ago). That said, should I bite the bullet and purchase genuine Volvo parts? Or can I go aftermarket? Or...Is it safe to assume that folks such as Delphi and NGK actually make these parts so I could get cheaper just going for the respective brand names (vs "Genuine Volvo")? Any advice on this topic would be greatly appreciated!

 

At my shop i only put in spark plugs from the dealer in a Volvo package. There were times during the 38 years I was in business that a specified aftermarket plug was incorrect - and cars would not run (early electronic ign v-6 is an example) So to prevent comebacks I had a no aftermarket plug rule. But sure there might be something compatible.

Coils were only replace When they were bad. Save your money for something else that will break.