Hello all, I have a rather simple question I believe, but anyway I was looking for the best higher end sparkplugs for a 1988 2.5 base coupe. What you have had the best luck with along with what shouldn't be put in it.
My car has a misfire and I've replaced basically everything else related that I could think of, so now my 3 year old plugs are next.

Standard copper core plugs as recommended by Pontiac.

You're wasting your money on anything else.

You have DIS engine w/ miss fire?
Exactly what was replaced & what brand & part # for new part?

Clean/fix all ground bolted/screwed to anything in engine bay & coat w/ silicone or permatex green label brake grease.

PIM/ICM Must have the shield. If not coils will damage the PIM have problems or start a fire.

"Cheap" Copper core AC or Autolite works. Warning: DIS Hates some "high end sparkplugs."
But these "cheap" plugs can rust fast depending on driving conditions etc.

See https://web.archive.org/web...~fierocave/gmdis.htm
https://www.fiero.nl/forum/...HTML/146263.html#p10
But seems autolite no longer make the "Double Platinum" APP666 & AC still list 41-816 @ $10 per plug @ most outlets.

When pulling any spark plugs...
Clean the hole before ever try using a wrench.
Turn them 1 turn max and clean again because you often loosen a lot more crap.

get some "canned air" if don't have any type of compressor to blow out trash and rust.
HD Lowes and sim often have it in cleaning or electric section.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

I'm not familiar with the term "dis" but I believe it is being that it has the coils. I have a suspicion that it in fact does not have the shield, I contacted the mechanic who worked on it and it aperantly dosent but not sure if they know what I meant.
Thanks I appreciate it and will have to look farther into that.

For parts I had replaced the coils with the MSD performance coils from the Fiero store, also replaced was throttle position sensor, map sensor, idle air control valve, and sparkplug wires that I can think of but I don't have the part number or brand for those.

It essentially has a misfire when it's in park, but when you put it in drive it stops doing it, dosent really do it much while driving but you can fell it missing uphill sometimes. It's one of those things that gradually gets worse with time, it will also die from the misfiring, and has died going down the road when not pressing the gas but I'm not sure if that's related.