'82 Chevy S10 rough idle after Spark Plug replacement

I've used Bosch plugs and they seemed to work ok. I've also used NGK, Champion, Autolite and AC with success. But, the only plugs that have ever given me any problems are the Champions (rust, cracked insulators) and the NGK's (just generally a very poor quality plug). I still prefer the AC plugs because they just work better.

****************************************** I would rather be exposed to the inconveniences attending too much liberty than to those attending too small a degree of it. ~ Thomas Jefferson ~

Not a question of "don't know why."

The subject has been beat to death in the automotive groups for years.

For starters;

One part # covering multiple heat ranges/OEM part numbers. i.e., ever see a Bosch Platinum speced for an engine with a .060" or .080" plug gap that actually allowed it to be gapped at .060" or.080"?

Wrong resistance compared to OEM.

Spark energy likes a sharp edge, the Bosch Platinum center electrode is flush with (shrouded by) the center porcelain, thus, no sharp edge.

With the shrouded center electrode, you can't really tell if it's actually the electrode of merely carbon filling the hole in the porcelain. (I've seen cases where the platinum tip was blown off allowing this to happen)

Chisel point on ground electrode has less area which erodes faster. > versus ]

Center electrode has less area, this will allow for fouling earlier than a plug with a larger sized center electrode.

On a DIS application, (half the plugs if Bosch Platinum) will have the platinum on the wrong polarity negating any benefit of the platinum.

The nanoseconds before the spark actually jumps the gap is a capacitive event, the sparkplug electrode is actually behaving as a plate storing electrons, you can't store as many electrons on the end of an itty-bitty wire electrode as you can a conventional sparkplug electrode.

Bosch Platinum +2 or +4 actually contribute to shrouding the spark, totally contrary for example, to why indexing spark plugs relative to the combustion chamber shows improvements in power. (The +2 and +4 schlockery casts a shadow of doubt on their whole sparkplug line)

Experience, you know, the thing that everyone complains that they can't find in a mechanic and then when they do, they dismiss it....

1) have seen a lot of vehicles that run like crap with them installed 2) problem went away when they were replaced with AC-Delco's

that's all the 'reason' I need

>

Well that was a great answer. When put this way I have an easier time accepting the point being made. While we are at it (I may as well make full use of your informed experience;) what do you think of those multi electrode sparkplugs that promise better perfromance and milage?

We have emission testing and I don't like moving off the beaten path incase the emissions get thrown off. I use AC delcos and other OEM ignition parts.

I know I broke at least one trying to adjust the gap, and that was the main issue with them, IIRC. Weren't welded very well, and would drop off into the cylinder. I've heard this many times about the Champions. I only use them in the lawn mower, and mainly because there is no alternative.