Changing spark plugs and spark plug wires.

[LLC5]

OK, I'll bite
After many years with return customers along with friends vehicles as well as my own I noticed some things related to this post.
Me and my fellow techs have repaired lots, and I mean lots or driveability problems by replacing the spark plugs. What we noticed is that engines that had NON-OEM plugs put in them the plugs didn't last very long. The trend that I noticed was whatever Champion lists for the interchange part for GM engines was to cold of a heat range.

GMs run poorly with Champions and autolites
Chryslers run poorly with ACDelco and autolites
Fords seem to run OK with most for a short time
Foreign cars couldn't tell you

Back in the early 90's I swapped a 2.8L V-6 from a Citation X-11 HO into my 84 T-10 Blazer 4-speed.
When ACDelco released rapid fire spark plugs I immediately installed them, holy cow ☺
It went from shifting to second at 25mph up to 29mph, my buddy could not pass me with his Fiero GT
By the time I had 20k on the plugs it was back to 25mph ��

My take is from day one just about all new plugs work fine but the incorrect ones degrade at a quicker rate.
I'll stick with iridiums for the consistent performance through their life

Any technicians working in an emissions testing state could tell us quite a bit about this I'm sure



Sent from my SM-T530NU using Tapatalk

You nailed it, stick with OEM parts on a stock street driven engine.

The comparison of the manufacturer's to spark plugs relationship is dead nuts on to what I have found over many (too many actually) decades of doing this. To answer the question about foreign Asian vehicles, it would be NGK as the plug to use. From the '70's to the present they are the plug of choice for foreign vehicles.