[Kath]

platinum is supposed to be 'bad' because of the reverse current 'waste spark' in the neon ignition system. This unduly erodes the platinum coating on the one tip, causing them to wear out much faster than platinum is advertised to last.

nobody should notice any real performance 'drop' though, at least not until such time as you erode that platinum coating away.

however, I tried some platinum +4's when i got my neon because the originals were aging and i really wanted to pamper the car. This was before reading up on the neon + platinum debacle. When i realized I had installed the wrong sort for a neon engine, I figured i'd give them a good 20k miles before pulling them out, thinking they wouldn't degrade overnight. strangely I noticed a decrease in idle quality, low rpm performance, and fuel economy, starting about 2 weeks after installation. When I pulled them out, the platinum wasn't eroded yet, i mean i only had them in for a month. They just really sucked as spark plugs in my neon. I suspect gapping was the issue, they just didn't spark well with any soot on them. Replaced them with iridiums, runs great.

So above and beyond platinum issues, I feel that the +2 and +4 design (whether platinum or not) is just a poor match for a neon. most cars have a larger gap than neons do. gm for example usually runs 45, not 35. that's a visually noticeable difference.

wouldn't gappable single prong spark plugs with platinum on *both* electrodes work fairly well though? I forget the brand, but i've seen those around. or platinums with a solid platinum alloy tip instead of a super thin coating? I mean hypothetically, looking at the science of why platinums degrade so fast in a waste spark system, I don't see why those particular sorts would be problematic.