Re: New here... tune up question
In terms of new plugs, you buy what you want. I prefer NGK V power, they seem to run good in any application I've thrown them into from vehicles to small engines. I figure $2.50 or so per plug for up to 50K versus $8 a plug for 80K, is a better value. Harder metals add to the durability but don't help with mileage in most cases.
90K on original plugs? I hope not.... My '99 coil pack is still original. I'm on my third set of wires. You may want to check the idle air controller on the throttle body as well. They're cleanable in most cases. Replacement is about $40, you pay double at the dealer. Injector cleaners may help, along with seafoam before you change out the old plugs.
'00 Durango R/T 360ci 290hp (modded); 138,500m
'06 Pontiac G6 GT 3.5L 220hp; 44,000m
'12 Chrysler 200 Limited 3.6L 283hp; 13,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!